[dev] Auth bug

[Chuck Hagenbuch]

Quoting KaalH! <kaalh@smol.org>:

> When login whith imp, the secret key used to store user info is "imp".
> So, in non-imp operation (ex: changing horde options), horde try to
> retrieve secret information with the "auth" key, this is the bug !

Try what I just committed... we _should_ have both keys, but I made sure
that IMP's login.php sets the Horde one if its doing Horde auth.

-chuck

--
Charles Hagenbuch, <chuck@horde.org>
"After a few minutes the most aromatic and nice smelling Italian coffee 
 will come out of the exhaustpipe." - Our stove-top espresso pot