Fix memory leak in cdr_sqlite3_custom.

(closes issue #13304)
Reported by: eliel
Patches:
      sqlite.patch uploaded by eliel (license 64)
      (Slightly modified by me)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@137933 65c4cc65-6c06-0410-ace0-fbb531ad65f3