Bug-1190: Fix for select response

Updated transact interface in OvsdbRPC to return JSON response and
deserializing to OperationResult being handled in OvsdbClientImpl

Change-Id: I061292435e68a638f83e69495710ffaa3a04479b
Signed-off-by: Sudheendra Murthy <sudhi.vm@gmail.com>
Merge "Bug-1190: Fix for select response" into topic/schema