Correct path for the default icon theme.

images/themes/default/theme.php

@@ -9,4 +9,4 @@
  * @package squirrelmail
  * @subpackage themes
  */
-$icon_themes[] = array('NAME'=>_("Default"),'PATH'=> SM_PATH.'images/');
+$icon_themes[] = array('NAME'=>_("Default"),'PATH'=> SM_PATH.'images/themes/default/');