Asterisk, when parking can drop rights a caller when a parking timeout occurs....

Asterisk, when parking can drop rights a caller when a parking timeout occurs.  Also, when doing built-in attended transfers, sometimes incorrectly passes rights from the transferrer to the transferee.  This patch tries to fixes the parking issue and lays some groundwork for later fixing the transfer issue.

(closes issue #11520)
Reported by: pliew
Tested by: otherwiseguy


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@105477 65c4cc65-6c06-0410-ace0-fbb531ad65f3