chan_sip: Clean leak on error path of process_sdp

Resolve leak in process_sdp that occurs in 2 error path's where
crypto lines are expected but not provided.

ASTERISK-24385 #close
Reported by: Corey Farrell
Review: https://reviewboard.asterisk.org/r/4045/
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Merged revisions 424569 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/12@424575 f38db490-d61c-443f-a65b-d21fe96a405b
Release AMI connections on shutdown.

ASTERISK-24378 #close
Reported by: Corey Farrell
Review: https://reviewboard.asterisk.org/r/4037/
........

Merged revisions 424578 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/12@424579 f38db490-d61c-443f-a65b-d21fe96a405b