Merge branch 'time_ago_fix' into 'master'

Time ago fix for branch compare page

https://dev.gitlab.org/gitlab/gitlabhq/issues/2508

See merge request !1904

app/views/projects/merge_requests/branch_from.js.haml

 :plain
   $(".mr_source_commit").html("#{commit_to_html(@commit, @source_project, false)}");
+  $('.js-timeago').timeago()

app/views/projects/merge_requests/branch_to.js.haml

 :plain
   $(".mr_target_commit").html("#{commit_to_html(@commit, @target_project, false)}");
+  $('.js-timeago').timeago()