server+netann+peer: put peer's alias in Update, proper config for link

This commit modifies the netann subsystem to use the peer's alias
for ChannelUpdates where appropriate (i.e. in case we are sending
the alias to the peer). It also modifies the loadActiveChannels
function in the peer package to handle upgrading a channel when the
scid-alias feature bit is turned on.

peer/test_utils.go

@@ -340,7 +340,11 @@ func createTestPeer(notifier chainntnfs.ChainNotifier,
 		OurPubKey:                aliceKeyPub,
 		OurKeyLoc:                testKeyLoc,
 		IsChannelActive:          func(lnwire.ChannelID) bool { return true },
-		ApplyChannelUpdate:       func(*lnwire.ChannelUpdate) error { return nil },
+		ApplyChannelUpdate: func(*lnwire.ChannelUpdate,
+			*wire.OutPoint, bool) error {
+
+			return nil
+		},
 	})
 	if err != nil {
 		return nil, nil, nil, err