res_pjsip: Handle reloading when permanent contacts exist and qualify is configured.

This change fixes a problem where permanent contacts being qualified were not
being updated. This was caused by the permanent contacts getting a uuid and not a
known identifier, causing an inability to look them up when updating in the
qualify code. A bug also existed where the new configuration may not be available
immediately when updating qualifies.

(closes issue ASTERISK-23514)
Reported by: Richard Mudgett

Review: https://reviewboard.asterisk.org/r/3448/
........

Merged revisions 412551 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@412552 65c4cc65-6c06-0410-ace0-fbb531ad65f3