Tweak to RSeq check; check RSeq if a reliable provisional comes in when we didn't use Require: 100rel, but used Supported: 100rel instead. Also, don't treat Supported: 100rel in a provisional response as indicating reliability. (3262 says reliable provisionals MUST have a Require: 100rel and an RSeq)
main/resip/dum/ClientInviteSession.cxx
main/resip/dum/InviteSession.cxx