Grow: close file descriptor earlier to avoid "still in use" when stopping

Grow: close file descriptor earlier to avoid "still in use" when stopping

Close fd2 as soon as it is no longer needed, before calling
Grow_continue(). Otherwise, we won't be able to stop an array with
external metadata during reshape, because mdadm running in background
will be keeping it open.

Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com>
Signed-off-by: Pawel Baldysiak <pawel.baldysiak@intel.com>
Signed-off-by: NeilBrown <neilb@suse.com>