Tidy "gateway name - IP" in dropdown list

While I notice this also, for a plain gateway, the current IP address is also listed in the dropdown list text, like "WAN_DHCP - 10.42.11.1". If there is no IP address currently, it might say "WAN_DHCP - dynamic". But for some DHCP gateways that have not had any non-default manual settings done, it can say "OPT1_DHCP -". This gets rid of the silly-looking "-"