Drop SS7 call if not connected yet when INCOMPLETE/BUSY/CONGESTION.

SS7 is a trunk protocol and should clear a failed call as soon as
possible.

* Made SS7 hangup a call immediately if it has not connected yet for
INCOMPLETE/BUSY/CONGESTION causes.  Otherwise, play an appropriate inband
tone.

(closes issue ASTERISK-19372)
Reported by: Igor Nikolaev
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Merged revisions 358278 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 358284 from http://svn.asterisk.org/svn/asterisk/branches/10


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@358307 65c4cc65-6c06-0410-ace0-fbb531ad65f3