check_memory: fix sortorder

check_memory

@@ -111,7 +111,7 @@ cat /proc/meminfo | egrep "^(Mem|Cache|Buffers|Swap|Slab|SReclaimable)"
 if [ $ramUsage -gt $iMinRamUsageToShowProcesses ]; then
   echo
   echo "RAM usage is higher $iMinRamUsageToShowProcesses percent ... showing most consuming processes:"
-  ps aux | head -1; ps aux | sort -nrk 3,3 | head -n 5
+  ps aux | head -1; ps aux | sort -nrk 4 | head -n 5
 fi 
 
 # --- performance data