Use btn-danger for delete button.

app/views/snippets/_actions.html.haml

@@ -6,7 +6,7 @@
     = link_to edit_snippet_path(@snippet), class: "btn btn-grouped snippable-edit" do
       Edit
   - if can?(current_user, :admin_personal_snippet, @snippet)
-    = link_to snippet_path(@snippet), method: :delete, data: { confirm: "Are you sure?" }, class: "btn btn-grouped btn-warning", title: 'Delete Snippet' do
+    = link_to snippet_path(@snippet), method: :delete, data: { confirm: "Are you sure?" }, class: "btn btn-grouped btn-danger", title: 'Delete Snippet' do
       Delete
 - if current_user
   .visible-xs-block.dropdown