Don't set up an ongoing connection to myself.

It is entirely possible that the configuration file could contain a
ConnectTo statement refering to its own name; that's a reasonable
scenario when one deploys semi-automatically generated tinc.conf files.

Amusingly, tinc does not like that at all, and actually sets up an
outgoing_t structure to myself (which obviously makes no sense). This is
mostly benign, though it does result in non-sensical "Already connected
to myself" messages every retry interval.

However, that also makes things blow up in close_network_connections(),
because there we delete the entire outgoing list and *then* the myself
node, which still has a reference to the freshly deleted outgoing
structure. Boom.

src/net_socket.c

@@ -800,6 +800,11 @@ void try_outgoing_connections(void) {
 			continue;
 		}
 
+		if(!strcmp(name, myself->name)) {
+			free(name);
+			continue;
+		}
+
 		bool found = false;
 
 		for list_each(outgoing_t, outgoing, outgoing_list) {