Fix Jabber/XMPP distributed MWI

The mailbox and context are swapped on the receiving end for all users
of Jabber and XMPP distributed MWI in Asterisk 1.8 and all more recent
versions. This swaps those values to be correct when publishing to the
internal event system from Jabber/XMPP distributed MWI state.

(closes issue ASTERISK-22435)
Reported by: abelbeck
Tested by: Michael Keuter
Patches:
    asterisk-1.8-res_jabber-aji_handle_pubsub_event.patch uploaded by abelbeck
    asterisk-11-res_xmpp-xmpp_pubsub_handle_event.patch uploaded by abelbeck


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/1.8@398523 f38db490-d61c-443f-a65b-d21fe96a405b