bsg: silence a bogus gcc warning

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/bsg.c b/block/bsg.c
index 6f05a39..9d77a0c 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -302,7 +302,7 @@
 {
 	request_queue_t *q = bd->queue;
 	struct request *rq;
-	int ret, rw;
+	int ret, rw = 0; /* shut up gcc */
 	unsigned int dxfer_len;
 	void *dxferp = NULL;