EWS bubble hover shows wrong timestamps
https://bugs.webkit.org/show_bug.cgi?id=137252

Reviewed by Alexey Proskuryakov.

Add "Z" suffix to timestamps to make sure if it is handled as UTC time.

* QueueStatusServer/handlers/queuestatusjson.py:
(QueueStatusJSON.get):
* QueueStatusServer/handlers/statusbubble.py:
(StatusBubble._iso_time):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@174343 268f45cc-cd09-0410-ab3c-d52691b4dbfc