Send a generic return result when we receive a CallDeflection facility message in chan_misdn.

ETSI 300-196 implies that a facility return result without arguments does
not have the operation-value.  This fact implies for ETSI that you can
only use the invoke-id to match requests with responses.


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@212199 65c4cc65-6c06-0410-ace0-fbb531ad65f3