Hardcoded link in admin/index.php in Moodle 1.8.7+

Hi,

Since the latest build contains this bug, I report it.
Everyone is involved who's using 1.8.7+ and a different admin path (specified in the config.php: $CFG->admin).

I'm an upgrader from 1.6.3 to 1.8 and then to 1.9

The 1.8 upgrade is going well till paypal and then clicking on continue I get error 500. The admin site of moodle died.
Now, I tracked back the issue to a hardcoded link in admin/index.php line 429:
require_once($CFG->dirroot.'/admin/mnet/adminlib.php');

It seems to already be fixed in 1.9 latest, but not in 1.8.7+.
Thanks and Happy new year!