handle_request_invite revise comment, fix coding guideline issues

I'm working with this code right now trying to analyze a deadlock.
This change is just to clean up a few things before I make a more
complex patch.



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@247915 65c4cc65-6c06-0410-ace0-fbb531ad65f3