corrected branch select if statement

lgsm/functions/update_factorio.sh

@@ -76,7 +76,7 @@ fn_update_factorio_arch(){
 
 fn_update_factorio_availablebuild(){
 	# Gets latest build info.
-	if [ "${branch}" ]; then
+	if [ "${branch}" != "stable" ]; then
 		availablebuild=$(${curlpath} -s https://www.factorio.com/download-headless/"${branch}" | grep 'headless/linux64' | head -n 1 | grep -oP '(?<=get-download/).*?(?=/)')
 	else
 		availablebuild=$(${curlpath} -s https://www.factorio.com/download-headless | grep 'headless/linux64' | head -n 1 | grep -oP '(?<=get-download/).*?(?=/)')