Generate an auth encryption key of at least 32 chars

It needs that many characters for seeding the Crypto routines.
According to [bnc#883823](https://bugzilla.suse.com/show_bug.cgi?id=883823) the AES key needs to be 16, 24, or 32 bytes long, so this code doesn't make sense to me as it could easily cause the length to be something else (e.g. 36 since `random_password` defaults to length 12, and 36 is the smallest multiple of 12 greater than 32).  Why not just do `random_password(32)` ?