Don't set up an ongoing connection to myself.

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.