Defer sending the connected line reinvite if a reinvite is already in progress.

(issue ASTERISK-19355)
Reported by: tomaso

(closes issue AST-825)
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Merged revisions 358162 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 358163 from http://svn.asterisk.org/svn/asterisk/branches/10


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@358164 65c4cc65-6c06-0410-ace0-fbb531ad65f3