Use LDAP add/mod operation instead of Kerberos to set the machine
account password.

There was an issue in AD where if PacRequestorEnforcement was set to '2'
setting the machine account password via Kerberos would be rejected.
This is already fixed on the AD side bit this patch which was created
with the help of David Mulder <dmulder@suse.com> might still be useful
if setting the machine account password with Kerberos might fail.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2039349
Resolves: #27