MDL-17458 prevent trailing whitespace problems in config.php

config-dist.php

@@ -342,6 +342,5 @@ if (file_exists("$CFG->dirroot/lib/setup.php"))  {       // Do not edit
     }
     die;
 }
-// MAKE SURE WHEN YOU EDIT THIS FILE THAT THERE ARE NO SPACES, BLANK LINES,
-// RETURNS, OR ANYTHING ELSE AFTER THE TWO CHARACTERS ON THE NEXT LINE.
-?>
+// There is no php closing tag in this file,
+// it is intentional because it prevents trailing whitespace problems!