mc: adjust FTB server pack check to look in subdirs

minecraft-server/start-deployFTB

@@ -68,7 +68,7 @@ if [[ $startScriptCount = 0 ]]; then
   unzip -o ${srv_modpack} -d ${FTB_BASE_DIR} | awk '{printf "."} END {print ""}'
 fi
 
-if [ ! -f ./ServerStart.sh ]; then
+if [[ $(find ${FTB_BASE_DIR} -name ServerStart.sh |wc -l) = 0 ]]; then
     echo "Please make sure you are using the server version of the FTB modpack!"
     exit 2
 fi