[krbdev.mit.edu #6546] KDB should use enctype of stashed master key

[Greg Hudson via RT]

The problem is actually more constrained than I actually thought.  If
you have a stashed master key, master key retrieval works just fine
regardless of the default master key enctype.  However, there are two
big caveats:

1. When you start up kadmind or kadmin.local, the kadmin/history key is
retrieved using krb5_dbe_find_enctype with the default master key
enctype specified; this fails if the database was created with a
different master key enctype.  This is easy to fix and will be fixed
shortly.

2. If you type out the key using krb5kdc -m, you get:

krb5kdc: Unable to decrypt latest master key with the provided master key
 - while fetching master keys list for realm TEST.ORG

if the master key enctype is not the default (and is not specified via
the -k option).  We can be friendlier than that, by looking up the key
type in the K/M entry.  This is a little less trivial to fix.