Don't resolve numeric hosts or contact unresolved hosts

If a SIP dial string contains a numeric hostname that is not a peer name,
don't try to resolve it as it is unlikely that someone really means
Dial(SIP/0.0.4.26) when Dial(SIP/1050) is called. Also, make sure that
create_addr returns -1 if an address isn't resolved so that we don't
attempt to send SIP requests to an address that doesn't resolve.

(closes issue ASTERISK-17146, ASTERISK-17716)

Review: https://reviewboard.asterisk.org/r/1532/
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Merged revisions 341314 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 341315 from http://svn.asterisk.org/svn/asterisk/branches/10


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@341316 65c4cc65-6c06-0410-ace0-fbb531ad65f3