Merge branch 'add_avatar_to_issue_mr_header' into 'master'

Add avatar to issue and MR pages header

closes #14395
# For Issues

### Before
![Screen_Shot_2016-03-18_at_4.27.25_PM](/uploads/b097c8e304c9737e2f46ee25667829bf/Screen_Shot_2016-03-18_at_4.27.25_PM.png)

### After
![Screen_Shot_2016-03-18_at_4.22.10_PM](/uploads/f7d2b12c9455950c2e660b33e27c1827/Screen_Shot_2016-03-18_at_4.22.10_PM.png)

# For Merge Request

### Before
![Screen_Shot_2016-03-18_at_4.27.09_PM](/uploads/50c7b6ee346f749f448647004ae6031b/Screen_Shot_2016-03-18_at_4.27.09_PM.png)

### After
![Screen_Shot_2016-03-18_at_4.24.17_PM](/uploads/abd37ccf030e0b6d10521a6937206de6/Screen_Shot_2016-03-18_at_4.24.17_PM.png)

See merge request !3301

app/views/projects/issues/show.html.haml

@@ -32,9 +32,9 @@
             = time_ago_with_tooltip(@issue.created_at)
             by
             %strong
-              = link_to_member(@project, @issue.author, avatar: false, size: 24, mobile_classes: "hidden-xs")
+              = link_to_member(@project, @issue.author, size: 24, mobile_classes: "hidden-xs")
             %strong
-              = link_to_member(@project, @issue.author, avatar: false, size: 24, mobile_classes: "hidden-sm hidden-md hidden-lg",
+              = link_to_member(@project, @issue.author, size: 24, mobile_classes: "hidden-sm hidden-md hidden-lg",
                 by_username: true, avatar: false)
 
     .pull-right.issue-btn-group

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

@@ -19,9 +19,9 @@
         = time_ago_with_tooltip(@merge_request.created_at)
         by
         %strong
-          = link_to_member(@project, @merge_request.author,  avatar: false, size: 24, mobile_classes: "hidden-xs")
+          = link_to_member(@project, @merge_request.author, size: 24, mobile_classes: "hidden-xs")
         %strong
-          = link_to_member(@project, @merge_request.author,  avatar: false, size: 24, mobile_classes: "hidden-sm hidden-md hidden-lg",
+          = link_to_member(@project, @merge_request.author, size: 24, mobile_classes: "hidden-sm hidden-md hidden-lg",
             by_username: true, avatar: false)
 
   .issue-btn-group.pull-right