Merge branch 'remove-redundant-last-push' into 'master'

Remove redundant last push event if activity feed is set to main page

### What does this MR do?

This MR eliminates a redundant last push event message if the user's preferences are set to the main activity feed.

### Why was this MR needed?

Lots of wasted space was introduced as a result.

### Screenshots

#### Before

![image](https://gitlab.com/stanhu/gitlab-ce/uploads/e7fdeb58b2017ec45443bf0d54a94685/image.png)

#### After

![image](https://gitlab.com/stanhu/gitlab-ce/uploads/d4a15113127be119e7c33ff501020f16/image.png)

### What are the relevant issue numbers?

Closes #2009

See merge request !995

app/views/projects/show.html.haml

@@ -6,7 +6,9 @@
   = render 'shared/no_ssh'
   = render 'shared/no_password'
 
-= render 'projects/last_push'
+- if prefer_readme?
+  = render 'projects/last_push'
+
 = render "home_panel"
 
 .project-stats