more consistent across different methodst

We shouldn't pass a non-existing branch to source_branch.
Checkout test for:

* spec/features/tags/master_views_tags_spec.rb:24
* spec/features/projects/files/project_owner_sees_link_to_create_license_file_in_empty_project_spec.rb:13

by checking filename as well

have the branch existed upfront. That is,
`Rugged::Commit.create` rather than `Gitlab::Git::Blob.commit`
which the former doesn't need to have the branch but the latter
needs.

So we still commit outside the hooks, and only
update ref inside the hooks. There are only two
exceptions:

* Whenever it's adding a tag. We can't add a tag
  without committing, unfortunately. See !7700
* Whenever source project is in another repository.
  We'll need to fetch ref otherwise commits can't be made.

See the whole discussion starting from:
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7237#note_19210942

Feedback:
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7237/diffs#note_19210818

Add back check if we're losing commits in a merge.

git operation inside GitHooksService. Feedback:

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7237#note_19210942

TODO: Fix tests for update_branch_with_hooks

* upstream/master: (288 commits)
  Added a changelog entry
  WIP: Adds a default commit message when adding a README (#25167)
  Change prop name to keep consistency with other props.
  Adds changelog entry
  Change ref property to commitRef
  Test all values for `enabled_git_access_protocol`
  Fixes ActionView::Template::Error: undefined method `text?` for nil:NilClass
  Simplify `branch_name` in bin/changelog
  Speed up project snippet security request specs
  Remove change to MWBS in code review guideline
  Enable ColorVariable in scss-lint
  Clean up common_utils.js (!7318)
  24726 Remove Across GitLab from side navigation
  Remove source sans pro
  Use system font
  Update CHANGELOG.md for 8.14.2
  Don't allow to specify a repo or version when installing Workhorse
  Fixed row margins on Pipeline Settings page in order to unify styles
  Fix URL rewritting in the Help section
  Allow public access to some Project API endpoints
  ...

If SSH prototol is disabled don't say the user requires SSH keys

Closes #24921

See merge request !7840

Use system font

Just for fun....   
### macOS Chrome (San Francisco):   
![Screen_Shot_2016-11-17_at_4.01.29_PM](/uploads/bfbab440ea0136314a6a7cffcd44f3ff/Screen_Shot_2016-11-17_at_4.01.29_PM.png)
### macOS Safari (San Francisco):   
![Screen_Shot_2016-11-18_at_8.28.22_AM](/uploads/3adc05d7adf84ca726cbaaf36cb0567d/Screen_Shot_2016-11-18_at_8.28.22_AM.png)
#### Ubuntu Firefox (Ubuntu): 
![Screen_Shot_2016-11-18_at_8.31.08_AM](/uploads/0f0d581d2d79d5db3dba9b2200499dc7/Screen_Shot_2016-11-18_at_8.31.08_AM.png)
#### Windows 7 IE 11 (Segoe UI): 
![Screen_Shot_2016-11-18_at_8.35.05_AM](/uploads/88efc2c554252de03fb84cc3c3e2856e/Screen_Shot_2016-11-18_at_8.35.05_AM.png)

See merge request !7545

Adds a default commit message when adding a README (#25167)

Closes #25167

See merge request !7903

Change ref property to commitRef

## What does this MR do?
Changes `ref` prop to `commitRef` because `ref` is a reserved word in Vue.js

## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?
Closes #25264

//cc @selfup

See merge request !7901

Clean up common_utils.js

## What does this MR do?

- Remove unused functions from `common_utils.js`.
- Move functions which are used from only one file to that file.

## Why was this MR needed?

Because some utils weren't that common (anymore).

See merge request !7318

Fixes ActionView::Template::Error: undefined method `text?` for nil:NilClass

Closes #25251

See merge request !7893

Enable ColorVariable in scss-lint

## What does this MR do?

- Enable the ColorVariable rule in`.scss-lint.yml`
- Change all color literals in `app/assets/stylesheets` to color variables

## Why was this MR needed?

- Enforce the usage of color variables to better constrain the various color values being used

## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- Tests
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?


Closes #23500

See merge request !7319

Fixed row margins on Pipeline Settings page in order to unify styles

On the ```project-name/pipelines/settings``` page, I removed the ```.row``` styling on ```.build-status``` and ```.coverage-report``` as it was causing those rows to not have the same margins as the "CI/CD Pipeline" row.

Now, they are even as you can see below:

![Screen_Shot_2016-12-01_at_12_54_59_PM](/uploads/a7196ff2e8efcdcd072bc2d26634a42d/Screen_Shot_2016-12-01_at_12_54_59_PM.png)

![Screen_Shot_2016-12-01_at_12_53_18_PM](/uploads/615428bab476fcd1baab86837395d800/Screen_Shot_2016-12-01_at_12_53_18_PM.png)

Closes #25098 
cc: @filipa

See merge request !7881

Simplify `branch_name` in bin/changelog

The `--short` option has existed since at least 1.8.1:
https://git-scm.com/docs/git-symbolic-ref/1.8.1

See merge request !7891

Speed up project snippet security request specs

Part of https://gitlab.com/gitlab-org/gitlab-ce/issues/24899

See https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7779 and
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7813

See merge request !7890

Use gitlab-workhorse 1.1.0. Adds Prometheus support and more.

See merge request !7868

The `--short` option has existed since at least 1.8.1:
https://git-scm.com/docs/git-symbolic-ref/1.8.1

Part of https://gitlab.com/gitlab-org/gitlab-ce/issues/24899

See https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7779 and
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7813