When calling the Realtime app more than once, unset fields which were

previously set are erroneously still set (Bug 6701).  After discussion,
it was determined this should only be changed in trunk.


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@49801 65c4cc65-6c06-0410-ace0-fbb531ad65f3