Merge branch 'dropdown-fix' into 'master'

Css fix for search dropdown overflow issue.

See merge request gitlab-org/gitlab-ce!20011

app/assets/stylesheets/pages/search.scss

@@ -114,7 +114,7 @@ input[type="checkbox"]:hover {
     }
 
     .dropdown-content {
-      max-height: 302px;
+      max-height: none;
     }
   }