Fix chan_h323 compilation

This fixes the things in chan_h323 that were missed or ignored in the
great channel opaquification and gets chan_h323 back into a compiling
state.

(closes issue ASTERISK-22365)
Reported by: Dmitry Melekhov
Patches:
    chan_h323.patch uploaded by Dmitry Melekhov
........

Merged revisions 398510 from http://svn.asterisk.org/svn/asterisk/branches/11
........

Merged revisions 398511 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@398512 65c4cc65-6c06-0410-ace0-fbb531ad65f3