[release/1.4.6] node, p2p: move network config out of Server

This silences a go vet message about copying p2p.Server in package node.

(cherry picked from commit 542b839ec7)

p2p/dial_test.go

@@ -478,7 +478,8 @@ func TestDialResolve(t *testing.T) {
 	}
 
 	// Now run the task, it should resolve the ID once.
-	srv := &Server{ntab: table, Dialer: &net.Dialer{Deadline: time.Now().Add(-5 * time.Minute)}}
+	config := Config{Dialer: &net.Dialer{Deadline: time.Now().Add(-5 * time.Minute)}}
+	srv := &Server{ntab: table, Config: config}
 	tasks[0].Do(srv)
 	if !reflect.DeepEqual(table.resolveCalls, []discover.NodeID{dest.ID}) {
 		t.Fatalf("wrong resolve calls, got %v", table.resolveCalls)