chan_console: Fix reference leaks to pvt.

Fix a bunch of calls to get_active_pvt
where the reference is never released.

ASTERISK-24504 #close
Reported by: Corey Farrell
Review: https://reviewboard.asterisk.org/r/4152/


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/12@427555 f38db490-d61c-443f-a65b-d21fe96a405b