* l_wait_event can now do interrupts without a timeout, if we're feeling brave.

* Big doc comment for l_wait_event.
* Only fire the timeout once from l_wait_event.
* Made timeout and the recovery-upcall path configurable via sysctl.
* Added OBD_FAIL_OSC codes for simulating simple client failure.
* Tentative rewiring of recovd into client connections, needs more thought
  and then more typing. We do fire the upcall, at least.
* Use the provided cluuid instead of NULL wherever it's handy already.
* Protect (feebly) against waiting for recovery that will never happen,
  in sync_io_timeout.
* Add timeouts to bulk operations in MDS and OST -- a recovery stub is now
  triggered, but nothing else.
* Document the unpleasant business in osc_brw_{read,write} as pertains to
  errors in the callbacks and cleanup of descriptors.
* Remove now-unused ptlrpc_check_bulk_{sent,received}.