Large diff to add support for last_rcvd file to OST.

Large diff to add support for last_rcvd file to OST.

- add obd_trans_info to the obd ops that modify data.  Currently it only includes
  the transo, but in future it will contain xid and other transaction specific data.
  Only the server side is using this structure, and is largely ignored on the client
  at this time.

- there is no support for actual recovery yet.

- Move the reconnection check from mds_connect() to target_handle_connect().

- marked code that needs to be removed for bug 550

- passes runtests on uml