Fixed issue with button color when no CI enabled

## What does this MR do?

Fixes an issue with the color of the merge button when no CI is setup.

## What are the relevant issue numbers?

Closes #17844

## Screenshots

![Screen_Shot_2016-05-25_at_09.58.44](/uploads/87aac74c5e2f8bfd2831e99c5915856d/Screen_Shot_2016-05-25_at_09.58.44.png)

See merge request !4287