When a device has failed, it needs to be removed from the personality
module before it can be removed from the array as a whole.
The first step is performed by md_check_recovery() which is called
from the raid management thread.

So when a HOT_REMOVE ioctl arrives, wait briefly for md_check_recovery
to have run.  This increases the chance that the ioctl will succeed.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NNeil Brown <nfbrown@suse.de>