ucs: only initialize when contact list is migrated

commit a58344becf4d0bc0518262492c3b9a79020120c4 changed UCS to always
fully initialize, because we needed it for buddy photos. That reason
went away with commit ce3df80c38e07f8879fb52a15467f5268fcba040.
Fix #263: ADFS fails when user and login name differ

Use authuser also for web ticket ADFS requests, if it is set. This will
fix failing ADFS authentication for users where the SIP user name is
different from the authentication name.
processing the response to presence publish event(SERVICE). For some lync servers, a publish does not trigger a notify. So the only way to update the state version number is to process this response.
purple: don't ignore status change when idle-away

commit 74820ce888af76c76c89e05d229aece0de33f443 added a check to ignore
state changes when the current libpurple state is idle or away. It is
not clear why this check was added. Simply remove it.

This should fix the long-standing issue that Pidgin status was not
returning to available after a meeting ended.