For extent locks (that are `asynchronous', that is, enqueued through ptlrpcd)

For extent locks (that are `asynchronous', that is, enqueued through ptlrpcd)
CLIO checks lock->l_granted_mode and accesses lock->l_lvb_data in its
completion AST and in the lock reply upcall (called from
osc_enqueue_fini()). As such things were never done in the pre-existing code,
execution of completion AST and reply upcall is not serialized.

Take lock and resource spin-locks manually to avoid races.

b=17927
i=oleg.drokin@sun.com
i=h.huang@sun.com