Fix PAN control callback definition to match what bluedroid is doing.

There's a discrepancy in the order of arguments between the interface
and the implementation. bluedroid swaps the |error| and |local_role|
arguments when calling back so this change redefines the interface
for consistency.

http://b/12853951

Change-Id: I0ccfc6d6d2002d647d484ab7f53744863b569502