Allow setqueuevar=yes (et al) to work, after changes to pbx_builtin_setvar()

(closes issue #12490)
Reported by: bcnit
Patches:
      12490-queuevars-3.diff uploaded by qwell (license 4)
Tested by: qwell


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@114540 65c4cc65-6c06-0410-ace0-fbb531ad65f3