Revert "kdc: move more name canonicalization logic to KDC"

This reverts commit 1b7e196e66.

It turns out that, contrary to the referrals draft, Windows does not
canonicalize enterprise principal names if the canonicalize KDC option is
unset.

lib/hdb/common.c

@@ -119,6 +119,7 @@ _hdb_fetch_kvno(krb5_context context, HDB *db, krb5_const_principal principal,
 	if (ret)
 	    return ret;
 	principal = enterprise_principal;
+	flags |= HDB_F_CANON; /* enterprise implies canonicalization */
     }
 
     hdb_principal2key(context, principal, &key);