Debug messages for pjsip outbound registration

Added debug messages indicating that an outbound registration attempt was made
and it was successful in pjsip.

(closes issue ASTERISK-22388)
Reported by: Rusty Newton
........

Merged revisions 398226 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@398227 65c4cc65-6c06-0410-ace0-fbb531ad65f3