sunrpc: don't attempt to cancel unitialized work

As of dc107402 "SUNRPC: make AF_LOCAL connect synchronous", we no longer initialize connect_worker in the
AF_LOCAL case, resulting in warnings like:

    WARNING: at lib/debugobjects.c:261 debug_print_object+0x8c/0xb0() Hardware name: Bochs
    ODEBUG: assert_init not available (active state 0) object type: timer_list hint: stub_timer+0x0/0x20
    Modules linked in: iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi nfsd auth_rpcgss nfs_acl lockd sunrpc
    Pid: 4816, comm: nfsd Tainted: G        W    3.8.0-rc2-00049-gdc107402 #801
    Call Trace:
     [<ffffffff8156ec00>] ? free_obj_work+0x60/0xa0
     [<ffffffff81046aaf>] warn_slowpath_common+0x7f/0xc0
     [<ffffffff81046ba6>] warn_slowpath_fmt+0x46/0x50
     [<ffffffff8156eccc>] debug_print_object+0x8c/0xb0
     [<ffffffff81055030>] ? timer_debug_hint+0x10/0x10
     [<ffffffff8156f7e3>] debug_object_assert_init+0xe3/0x120
     [<ffffffff81057ebb>] del_timer+0x2b/0x80
     [<ffffffff8109c4e6>] ? mark_held_locks+0x86/0x110
     [<ffffffff81065a29>] try_to_grab_pending+0xd9/0x150
     [<ffffffff81065b57>] __cancel_work_timer+0x27/0xc0
     [<ffffffff81065c03>] cancel_delayed_work_sync+0x13/0x20
     [<ffffffffa0007067>] xs_destroy+0x27/0x80 [sunrpc]
     [<ffffffffa00040d8>] xprt_destroy+0x78/0xa0 [sunrpc]
     [<ffffffffa0006241>] xprt_put+0x21/0x30 [sunrpc]
     [<ffffffffa00030cf>] rpc_free_client+0x10f/0x1a0 [sunrpc]
     [<ffffffffa0002ff3>] ? rpc_free_client+0x33/0x1a0 [sunrpc]
     [<ffffffffa0002f7e>] rpc_release_client+0x6e/0xb0 [sunrpc]
     [<ffffffffa000325d>] rpc_shutdown_client+0xfd/0x1b0 [sunrpc]
     [<ffffffffa0017196>] rpcb_put_local+0x106/0x130 [sunrpc]
    ...
Acked-by: N"Myklebust, Trond" <Trond.Myklebust@netapp.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

net/sunrpc/xprtsock.c

@@ -849,6 +849,14 @@ static void xs_tcp_close(struct rpc_xprt *xprt)
 		xs_tcp_shutdown(xprt);
 }
 
+static void xs_local_destroy(struct rpc_xprt *xprt)
+{
+	xs_close(xprt);
+	xs_free_peer_addresses(xprt);
+	xprt_free(xprt);
+	module_put(THIS_MODULE);
+}
+
 /**
  * xs_destroy - prepare to shutdown a transport
  * @xprt: doomed transport
@@ -862,10 +870,7 @@ static void xs_destroy(struct rpc_xprt *xprt)
 
 	cancel_delayed_work_sync(&transport->connect_worker);
 
-	xs_close(xprt);
-	xs_free_peer_addresses(xprt);
-	xprt_free(xprt);
-	module_put(THIS_MODULE);
+	xs_local_destroy(xprt);
 }
 
 static inline struct rpc_xprt *xprt_from_sock(struct sock *sk)
@@ -2482,7 +2487,7 @@ static struct rpc_xprt_ops xs_local_ops = {
 	.send_request		= xs_local_send_request,
 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
 	.close			= xs_close,
-	.destroy		= xs_destroy,
+	.destroy		= xs_local_destroy,
 	.print_stats		= xs_local_print_stats,
 };