AST-2014-003: res_pjsip: When handling 401/407 responses don't assume a...

AST-2014-003: res_pjsip: When handling 401/407 responses don't assume a request will have an endpoint.

This change removes the assumption that an outgoing request will always
have an endpoint and makes the authenticate_qualify option work once again.

(closes issue ASTERISK-23210)
Reported by: Joshua Colp
........

Merged revisions 410306 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@410307 65c4cc65-6c06-0410-ace0-fbb531ad65f3