Use the executable created by linuxgsm

[PJGame841]

When the linuxgsm creates the game server executable file, the entrypoint is assuming $GAMESERVER is the name of the exec. Or if the exec has been created before but is not executable (by the touch command) the linuxgsm will install a new instance (which have "-2" added to its name) but the script doesn't use this new name. So I just did a grep to get the new file name, and then replace the GAMESERVER env variable. This new value is then used to install, update and start the server.