handle kdb stash being a keytab
In krb5 1.7 and later, the stash file (/var/kerberos/krb5kdc/.k5.$REALM
on Fedora) is created in the regular keytab format instead of the older
less-portable one. Based from comments and code in kt_file.c, here's a
change to try to recognize that case (the file starts with a magic
number) and read the master key from Python.
The KDC will still read either format, so I left the bits that set
things up on replicas alone (advice appreciated). The patch works as
expected on my 64-bit box, both on RHEL5 (krb5 1.6.1 with a traditional
stash file) and on Raw Hide (krb5 1.7 with a keytab).
Backported from IPA v2 patch submitted by Nalin Dahyabhai <nalin@redhat.com>