Fix segfault caused by using rdev_for_each instead of rdev_for_each_safe
Commit 
dafb20fa34320a472deb7442f25a0c086e0feb33 mistakenly replaced a safe
iterator with an unsafe one when making some macro changes.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
        int ret;
        unsigned redundancy = 0;
        struct raid_dev *dev;
-       struct md_rdev *rdev, *freshest;
+       struct md_rdev *rdev, *tmp, *freshest;
        struct mddev *mddev = &rs->md;
 
        switch (rs->raid_type->level) {
        }
 
        freshest = NULL;
-       rdev_for_each(rdev, mddev) {
+       rdev_for_each_safe(rdev, tmp, mddev) {
                if (!rdev->meta_bdev)
                        continue;