Change our open to test for drv->heads like we do in other places in the
driver.  Mostly for consistency.
Signed-off-by: NMike Miller <mike.miller@hp.com>
Acked-by: NJens Axboe <jens.axboe@oracle.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>