Fix an RTP instance allocation failure on Solaris.

(closes issue #16543)
Reported by: crjw
Patches:
      rtp_sin_family.patch uploaded by crjw (license 963)
Tested by: crjw, qwell


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@241098 65c4cc65-6c06-0410-ace0-fbb531ad65f3