fix(minecraft): fix java ram assignment (#3147)

lgsm/config-default/config-lgsm/mcserver/_default.cfg

@@ -14,6 +14,7 @@ javaram="1024" # -Xmx$1024M
 ## Server Parameters | https://docs.linuxgsm.com/configuration/start-parameters#additional-parameters
 fn_parms(){
 parms="nogui"
+executable="java -Xmx${javaram}M -jar ${jarfile}"
 }
 
 ## Release Settings | https://docs.linuxgsm.com/game-servers/minecraft#release-settings
@@ -151,7 +152,8 @@ glibc="null"
 ## Game Server Directories
 systemdir="${serverfiles}"
 executabledir="${serverfiles}"
-executable="java -Xmx${javaram}M -jar ${serverfiles}/minecraft_server.jar"
+jarfile="${serverfiles}/minecraft_server.jar"
+executable="${jarfile}"
 servercfgdir="${systemdir}"
 servercfg="server.properties"
 servercfgdefault="server.properties"