only attempt to do stun handling on ipv4 or ipv4 mapped to ipv6 addresses

Patch by: jkonieczny (modified)
ASTERISK-18490
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Merged revisions 344330 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 344334 from http://svn.asterisk.org/svn/asterisk/branches/10


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@344335 65c4cc65-6c06-0410-ace0-fbb531ad65f3