Fixed 'make clean' for wiki docs
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Merged revisions 398198 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@398205 f38db490-d61c-443f-a65b-d21fe96a405b
Prevent a crash in res_pjsip_dtmf_info.c

This change makes sure that a content type header exists before
checking the contents of the header against known SIP INFO DTMF content
types.
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Merged revisions 398206 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@398207 f38db490-d61c-443f-a65b-d21fe96a405b