Cleanup Opp session during ACL disconnect

Process ACL_DISCONNECT message in OPP module to clean up
the transfer related data as soon as ACL is disconnected.
This removes the delay we observe in displaying File not received
message when Remote device's Battery is abbruptly taken out
or remote disconnects the ACL when authorization request is in
pending state in DUT.

Change-Id: Ie749990987e43a02636c4e573e706f615e58fe7b