libceph: create messenger with client

This simplifies the init/shutdown paths, and makes client->msgr available
during the rest of the setup process.

Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 15f65b5..0b3c566 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -260,7 +260,7 @@
 	kref_init(&rbdc->kref);
 	INIT_LIST_HEAD(&rbdc->node);
 
-	rbdc->client = ceph_create_client(opt, rbdc);
+	rbdc->client = ceph_create_client(opt, rbdc, 0, 0);
 	if (IS_ERR(rbdc->client))
 		goto out_rbdc;
 	opt = NULL; /* Now rbdc->client is responsible for opt */