[PATCH] make file leases work as they should

[PATCH] make file leases work as they should

This patch fixes the following problems in the file lease:
	when there are multiple shared leases on a file, all the
		lease holders get notified when someone opens the
		file for writing (used to be only the first).
	when a nonblocking open breaks a lease, it will time out
		as it should (used to never time out).

This should make the leases code more usable (hopefully).