orangefs: sanitize handling of request list

* checking that daemon is running (to decide whether we want to limit
the timeout) should be done *after* the damn thing is included into
the list; doing that before means that if the daemon gets shut down
in between, we'll end up waiting indefinitely (== up to kill -9).

* cancels should go into the head of the queue - the sooner they
are picked, the less work daemon has to do and the sooner we get to
free the slot held by aborted operation.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Mike Marshall <hubcap@omnibond.com>