md/raid5: Fix a bug about judging if the operation is syncing or replacing

md/raid5: Fix a bug about judging if the operation is syncing or replacing

When create a raid5 using assume-clean and echo check or repair to
sync_action.Then component disks did not operated IO but the raid
check/resync faster than normal.
Because the judgement in function analyse_stripe():
		if (do_recovery ||
		    sh->sector >= conf->mddev->recovery_cp)
			s->syncing = 1;
		else
			s->replacing = 1;
When check or repair,the recovery_cp == MaxSectore,so syncing equal zero
not one.

This bug was introduced by commit 9a3e1101b827
    md/raid5:  detect and handle replacements during recovery.
so this patch is suitable for 3.3-stable.

Cc: [email protected]
Signed-off-by: majianpeng <[email protected]>
Signed-off-by: NeilBrown <[email protected]>