Switch from hostname to an IP address in the SDP origin line.

Using the hostname in the SDP origin line may not satisfy the requirement
of RFC 4566 that we use a FQDN or IP address. This change has us use the
same information from the SDP connection line if possible. If not possible,
we'll use the configured media address. And if that's not possible, we use
the result of a PJLIB call to get the IP address of ourself.

ASTERISK-23994 #close
Reported by Private Name

Review: https://reviewboard.asterisk.org/r/3925
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Merged revisions 421796 from http://svn.asterisk.org/svn/asterisk/branches/12
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Merged revisions 421797 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@421798 65c4cc65-6c06-0410-ace0-fbb531ad65f3