Remove obsolete diagnostics code from ldap plugin

Signed-off-by: Bryn M. Reeves <bmr@redhat.com>
Ensure superclass postproc method is called in ldap plugin

Since the ldap plugins add files and post-processing methods at
multiple class levels (Ldap, RedHatLdap etc.) derived classes
must explicitly call their parent class's postproc() method to
apply all substitutions to collected data.

Signed-off-by: Bryn M. Reeves <bmr@redhat.com>