Merge branch 'remove-unnecessary-message-mr-commits-tab' into 'master'

Remove unnecessary commits order message

Remove unnecessary message. User should expect that commits are listed in reverse chronological order. Even if they are not initially clear, glancing quickly through the list informs them right away. No point in drawing unnecessary attention to extra information that is not main content. The other tabs also have lists in chronological or reverse chronological order. But there's nothing there to explain in which direction.

### Existing
<img src="/uploads/d5592533c60186a7a53af5d6d010fa56/Screen_Shot_2016-12-09_at_12.38.25_AM.png" height="200px" />

### After change
<img src="/uploads/facc800496d27f1ee33e0d48d339b2f3/Screen_Shot_2016-12-09_at_12.37.36_AM.png" height="200px" />

See merge request !8004

app/views/projects/merge_requests/show/_commits.html.haml

-.content-block.oneline-block
-  = icon("sort-amount-desc")
-  Most recent commits displayed first
-
 %ol#commits-list.list-unstyled
   = render "projects/commits/commits", project: @merge_request.source_project, ref: @merge_request.source_branch

changelogs/unreleased/remove-unnecessary-message-mr-commits-tab.yml

+---
+title: Remove unnecessary commits order message
+merge_request: 8004
+author: