plug a couple of memleaks in chan_skinny.

(closes issue #13452)
Reported by: pj
Patches:
      memleak5.diff uploaded by wedhorn (license 30)
Tested by: wedhorn, pj, mvanbaak

(closes issue #13294)
Reported by: pj


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@143082 65c4cc65-6c06-0410-ace0-fbb531ad65f3