[ticket/7252] Removed an outdated comment pertaining to PHP 4.x.

PHPBB3-7252

phpBB/includes/functions_posting.php

@@ -560,7 +560,6 @@ function get_supported_image_types($type = false)
 		if ($type !== false)
 		{
 			// Type is one of the IMAGETYPE constants - it is fetched from getimagesize()
-			// We do not use the constants here, because some were not available in PHP 4.3.x
 			switch ($type)
 			{
 				// GIF