More parking issues.

* Fix potential deadlocks in SIP and IAX blind transfer to parking.

* Fix SIP, IAX, DAHDI analog, and MGCP channel drivers to respect the
parkext_exclusive option with transfers (Park(,,,,,exclusive_lot)
parameter).  Created ast_park_call_exten() and ast_masq_park_call_exten()
to maintian API compatibility.

* Made masq_park_call() handle a failed ast_channel_masquerade() setup.

* Reduced excessive struct parkeduser.peername[] size.
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Merged revisions 341254 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 341255 from http://svn.asterisk.org/svn/asterisk/branches/10


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@341256 65c4cc65-6c06-0410-ace0-fbb531ad65f3