fs: logfs: remove unnecesary check

The check on bio->bi_vcnt doesn't make sense in erase_end_io().
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMing Lei <tom.leiming@gmail.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

fs/logfs/dev_bdev.c

@@ -143,7 +143,6 @@ static void erase_end_io(struct bio *bio)
 	struct logfs_super *super = logfs_super(sb); 
 
 	BUG_ON(bio->bi_error); /* FIXME: Retry io or write elsewhere */ 
-	BUG_ON(bio->bi_vcnt == 0); 
 	bio_put(bio); 
 	if (atomic_dec_and_test(&super->s_pending_writes))
 		wake_up(&wq);