Merge branch 'commit-header' into 'master'

Fixes header vertical centering.

Fixes header centering. 

![ss__2016-05-16_at_5.26.30_PM](/uploads/300b64afc6585023f0e0dbbf721c359a/ss__2016-05-16_at_5.26.30_PM.png)

cc @dzaporozhets 

See merge request !4170

app/assets/stylesheets/pages/commit.scss

@@ -26,6 +26,8 @@
 .commit-info-row {
   margin-bottom: 10px;
+  line-height: 24px;
+  padding-top: 6px;
   &.commit-info-row-header {
     line-height: 34px;

app/views/projects/commit/_commit_box.html.haml

@@ -6,10 +6,10 @@
   .pull-right.commit-action-buttons
     - if defined?(@notes_count) && @notes_count > 0
-      %span.btn.disabled.btn-grouped.hidden-xs
+      %span.btn.disabled.btn-grouped.hidden-xs.append-right-10
         = icon('comment')
         = @notes_count
-    = link_to namespace_project_tree_path(@project.namespace, @project, @commit), class: "btn btn-grouped hidden-xs hidden-sm" do
+    = link_to namespace_project_tree_path(@project.namespace, @project, @commit), class: "btn btn-default append-right-10 hidden-xs hidden-sm" do
       Browse Files
     .dropdown.inline
       %a.btn.btn-default.dropdown-toggle{ data: { toggle: "dropdown" } }