Fix typo

upgrade/Monit.sh

@@ -30,7 +30,7 @@ echo "" > ./$$-parts
 for part in "${list_of_part[@]}"
 do
     name=$(echo $part | sed -e 's@^/$@root@' -e 's@^/@@')
-    echo -e "check device $name with path $part\n    if SPACE usage > ${MEM_OVERLOAD_PERCENT:-75}% then alert\n\n" >> ./$$-parts
+    echo -e "check device $name with path $part\n    if SPACE usage > ${DISC_OVERLOAD_PERCENT:-75}% then alert\n\n" >> ./$$-parts
 done
 mv ./$$-parts /etc/monit/conf-available/disc
 ln -s /etc/monit/conf-available/disc /etc/monit/conf-enabled/