Fix two memory leaks in chan_gtalk, thanks Eliel!

(closes issue #13310)
Reported by: eliel
Patches:
      chan_gtalk.c.patch uploaded by eliel (license 64)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@139281 65c4cc65-6c06-0410-ace0-fbb531ad65f3