[krbdev.mit.edu #7733] afs3 salt contaminates later enctypes in the list at key generation time

[Benjamin Kaduk via RT]

Commit bc096a77ffdab283d77c2e0fc1fdd15b9f77eb41 removed the use of 
SALT_TYPE_AFS_LENGTH but introduced a bug wherein the s2k_params used for key generation 
was set to the afs3_params for afs3 salts, but never reset to NULL afterwards.
The pbkdf2 enctypes (aes, camellia) and the arcfour enctypes do checking on their input 
parameters for string-to-key (des3 does not) and return KRB5_ERR_BAD_S2K_PARAMS.  This was 
reported by Jason Edgecombe on the kerberos at mit.edu mailing list.
The afs3 salt should only affect the enctype it is associated with, not all subsequent enctypes.