LinuxGSM: Don't exit script when ip is 0.0.0.0

when the ip parameter in the config files is set to 0.0.0.0 the script prints an error

[ WARN ] Multiple active network interfaces

Manually specify the IP you want to use within the csgoserver script.
Set ip="0.0.0.0" to one of the following:

(The corresponding FAQ article is https://github.com/GameServerManagers/LinuxGSM/wiki/FAQ#-warn--multiple-active-network-interfaces )

I have multiple problems with this:

1. It prints a warning and then the script exits. Warnings should not should prohibit the server start. Critical events do that.
2. It is sometimes required to run the server with a 0.0.0.0 ip, because in the case of many srcds-based servers it’s needed for many LAN settings. If you do not have a -ip setting the server will bind it’s rcon to 127.0.1.1 and will therefore not be reachable from the network if you add a -ip setting that is not 0.0.0.0 the server only binds to that ip and does not listen to broadcast traffic anymore, therefore it is not found by the LAN server browser anymore. (sv_lan 1 is required for this to work)

Possible workarounds are modifying the start-parameters and adding a valid ip variable that is not used at all. e.g. adding somethin like this to the lgsm config files:

ip=1.2.3.4
fn_parms(){
parms="-game fof -strictportbind -ip 0.0.0.0 -port ${port} +clientport ${clientport} +tv_port ${sourcetvport} +map ${defaultmap} +servercfgfile ${servercfg} -maxplayers ${maxplayers}"
} 

But this means that updates on the startup parameters are ignored. This is not a nice solution.