radius: distinguish between User-Request and Admin-Reset.

radius: distinguish between User-Request and Admin-Reset.

For the purposes of our definition:

User-Request - remote side hanging up.
Admin-Reset - local side hanging up.

Reasoning is that typically radius will be used to authentication
dial-in users, so if the pppd gets killed locally, that's not the User
(client) requesting hangup, but rather the local administrator (be that
a manual kill, or as a result of a CoA/Disconnect).

Signed-off-by: Jaco Kroon <jaco@uls.co.za>