Fix error on /groups/groupID/users/userID PUT that made no changes
Fix error on /groups/groupID/users/userID PUT that made no changes


grumbelbart/zotero_dataserver_sualk,zebulon2/dataserver,grumbelbart/zotero_dataserver_sualk,zebulon2/dataserver,grumbelbart/zotero_dataserver_sualk,zebulon2/dataserver,grumbelbart/zotero_dataserver_sualk,zebulon2/dataserver