lnd: drop the port from the default rpc host

Drop the port from the default RPC host as the proper port will be
filled in depending on which net is chosen.

config.go

@@ -21,7 +21,7 @@ const (
 	defaultRPCPort        = 10009
 	defaultSPVMode        = false
 	defaultPeerPort       = 10011
-	defaultRPCHost        = "localhost:18334"
+	defaultRPCHost        = "localhost"
 	defaultRPCUser        = "user"
 	defaultRPCPass        = "passwd"
 	defaultSPVHostAdr     = "localhost:18333"