Re-order help entries in populate.

tools/populate.in

@@ -13,15 +13,15 @@ doHelp() {
     cat <<_EOF_
 $myname [-f] [-v] -s source_root -d destination_root
 
-    -f  force execution: if destination directory already exists,
-        it will be removed first.
-
     -s dir
         use 'dir' as the un-populated (source) root directory
 
     -d dir
         use 'dir' as the place to put the populated root directory
 
+    -f  force execution: if destination directory already exists,
+        it will be removed first.
+
     -v  Be verbose
 _EOF_
 }