sunrpc: Remove useless if (task == NULL) from xprt_reserve_xprt

The task in question is dereferenced above (and is actually never NULL).
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Reviewed-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

net/sunrpc/xprt.c

@@ -199,8 +199,6 @@ int xprt_reserve_xprt(struct rpc_task *task)
 	if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
 		if (task == xprt->snd_task)
 			return 1;
-		if (task == NULL)
-			return 0;
 		goto out_sleep;
 	}
 	xprt->snd_task = task;