r17616: Add the lm and nt hashes to the cached credentials

r17616: Add the lm and nt hashes to the cached credentials
stored - only store the password if we're going to
be doing a krb5 refresh. GD please review this change !
Now to add code to reference count the cached creds
(to allow multiple pam_logon/pam_logoffs to keep the
creds around), ensure that the cred cache is called
on all successful pam_logons (if we have winbindd cache
pam credentials = true, set this by default) and finally
ensure the creds cache is changed on successful password
change. GD - you *really* need to review this :-).
Jeremy.
(This used to be commit 017e7e14958d29246a1b221e33755bb91e96b08f)