ast_channel_masquerade: Avoid recursive masquerades.

ast_channel_masquerade: Avoid recursive masquerades.

Check all 4 combinations of (original/clonechan) * (masq/masqr).

Initially original->masq and clonechan->masqr were only checked.

It's possible with multiple masq's planned - and not yet executed, that
 the 'original' chan could already have another masq'd into it - thus original->masqr
would be set, that masqr would lost.
Likewise for the clonechan->masq.

(closes issue #16057;#17363)
Reported by: amorsen;davidw,alecdavis
Patches:
      based on bug16057.diff4.txt uploaded by alecdavis (license 585)
Tested by: ramonpeek, davidw, alecdavis

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.6.2@287685 65c4cc65-6c06-0410-ace0-fbb531ad65f3