Remove keystone configs for ldap read/write
Remove keystone configs for ldap read/write

Configuration options that toggle support for LDAP read/write
were deprecated and removed as of the Ocata release:

  I13eada3d5c3a166223c3e3ce70b7054eaed1003a

This means we no longer need to clutter the domain-specific
configuration with these values since they are no longer used.

Change-Id: I23b5b994862f066c3d48ce524c396faecabf60f8

nawawi/openstack,nawawi/openstack,group-policy/devstack,dtroyer/devstack,noironetworks/devstack,group-policy/devstack,dtroyer/devstack,openstack-dev/devstack,openstack-dev/devstack,noironetworks/devstack