md: fix error paths from bitmap_create.

Recent change to bitmap_create mishandles errors.
In particular a failure doesn't alway cause 'err' to be set.

Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
NeilBrown 2015-02-25 11:44:11 +11:00
commit ba599aca52