res_parking: Misc fixes.

res/parking/parking_applications.c:

* Add malloc fail checks in setup_park_common_datastore().

* Fix playing parking failed announcement to only happen on non-blind
transfers in park_app_exec().  It could never go out before because a test
was provedly always false.

res/parking/parking_bridge.c:

* Fix NULL tolerance in generate_parked_user() because
bridge_parking_push() can theoretically pass a NULL parker channel if the
parker channel went away for some reason.

* Clarify some weird code dealing with blind_transfer in
bridge_parking_push().

res/parking/parking_bridge_features.c:

* Made park_local_transfer() set BLINDTRANSFER on the Local;1 channel
which will be bulk copied to the Local;2 channel on the subsequent
ast_call().  The additional advantage is if the parker channel has the
BLINDTRANSFER and ATTENDEDTRANSFER variables set they are now guaranteed
to be overridden.

res/parking/parking_manager.c:

* Fix AMI Park action input range checking of the Timeout header in
manager_park().

* Reduced locking scope to where needed in manager_park().

res/res_parking.c:

* Fix some off nominal missing unlocks by eliminating the returns.

Change-Id: Ib64945bc285acb05a306dc12e6f16854898915ca