Resetting a single user's token does not use the configured token length

To reproduce:

1. Enable the Token Authentication module.
2. In Administration > Site Configuration > Token Authentication, change the token length to something other than 10.
3. Log in as any user.
4. Go to "My account" and select the Token Authentication tab.
5. Click Reset Token, and confirm that you want to reset the token.

Expected result: the new token has the length configured in step #2.
Actual result: the new token as the default length, 10.

A patch is attached.