use relative protocol urls for google api in the admin backend

git-svn-id: https://plugins.svn.wordpress.org/events-made-easy/trunk@840456 b8457f37-d9ea-0310-8a92-e5e31aec5664
in the event edit window, the ajax method for removing rsvp's wasn't working anymore

git-svn-id: https://plugins.svn.wordpress.org/events-made-easy/trunk@840457 b8457f37-d9ea-0310-8a92-e5e31aec5664