md: make sure GET_ARRAY_INFO ioctl reports correct "clean" status

If an array has a bitmap, the when we set the "has bitmap" flag we
incorrectly clear the "is clean" flag.

"is clean" isn't really important when a bitmap is present, but it is
best to get it right anyway.

Reported-by: George Duffield <forumscollective@gmail.com>
Link: http://lkml.kernel.org/CAG__1a4MRV6gJL38XLAurtoSiD3rLBTmWpcS5HYvPpSfPR88UQ@mail.gmail.com
Fixes: 36fa306 (v2.6.14)
Signed-off-by: NeilBrown <neilb@suse.de>

drivers/md/md.c

@@ -5599,7 +5599,7 @@ static int get_array_info(struct mddev * mddev, void __user * arg)
 	if (mddev->in_sync)
 		info.state = (1<<MD_SB_CLEAN);
 	if (mddev->bitmap && mddev->bitmap_info.offset)
-		info.state = (1<<MD_SB_BITMAP_PRESENT);
+		info.state |= (1<<MD_SB_BITMAP_PRESENT);
 	info.active_disks  = insync;
 	info.working_disks = working;
 	info.failed_disks  = failed;