Merge branch 'dropdown-enter-select-fix' into 'master'

Fixed issue with enter key not selecting correct value in dropdown



See merge request !3563

app/assets/javascripts/gl_dropdown.js.coffee

@@ -394,7 +394,7 @@ class GitLabDropdown
       selector = ".dropdown-page-one #{selector}"
 
     # simulate a click on the first link
-    $(selector).trigger "click"
+    $(selector, @dropdown).trigger "click"
 
   addArrowKeyEvent: ->
     ARROW_KEY_CODES = [38, 40]