Fix outbound DTMF for inband mode (tell asterisk core to generate DTMF

sounds).

(Closes issue ASTERISK-19233)
Reported by: Matt Behrens
Patches:
        chan_ooh323.c.patch uploaded by Matt Behrens (License #6346)
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Merged revisions 352807 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 352817 from http://svn.asterisk.org/svn/asterisk/branches/10


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@352821 65c4cc65-6c06-0410-ace0-fbb531ad65f3