res_pjsip_session: Set options (100rel, timers) on incoming sessions.

This change passes options to the UAS creation function. This in turn
sets up 100rel and session timer properties on the incoming session.

Reported by Julian Russell on asterisk-users mailing list.
........

Merged revisions 409287 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@409288 65c4cc65-6c06-0410-ace0-fbb531ad65f3