- added connection structure which encompasses some (but perhaps not enough yet)

- added connection structure which encompasses some (but perhaps not enough yet)
HA elements and a lustre_peer.  see rpc/connection.c or lustre_net.h for the
very-simple API
- removed many duplicated structure entries from the RPC path
- broke local_lock_enqueue into two functions; create the lock, do the remote
operation, do the local operation.
- the shadow local lock tree is implemented, but not tested.