protocols running atop ACL/L2CAP needs to be able to track pdus based on

protocols running atop ACL/L2CAP needs to be able to track pdus based on
acl chandle + direction + l2cap-CID    to uniquely identify a single specific
flow of PDU packets.

So we need to pass the chandle upp from acl to l2cap at least.

It would have been nice to handle this using "conversations" but the bluetooth
stack does not eaily map to the idiom host:port<->host:port

instead in bluetooth you have unidirectional flows that are identified by ACL-chandle:L2CAP-CID:direction     and additional state held inside l2cap  would attach two such flows together into a "conversation".
Bluetooth packets themself    only indentify "half" of the two way conversation.

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@18218 f5534014-38df-0310-8fa8-9805f1628bb7