*_attribute_ignore is deprecated for removal even ldap backend read operations depends on it

[Dave Chen]

`user_attribute_ignore` or `group_attribute_ignore` are both needed
by identity ldap backend to judge whether a specific attributes should
be returned for read user or group operations.

We cannot deprecated those property as keystone still support read operations with ldap backend.

One occurence could be found from [1] where the logic is implemented
in `_ldap_res_to_model` method.

[1] https://github.com/openstack/keystone/blob/093d14fa9196c42f859d4a399bb2e423934a9972/keystone/identity/backends/ldap/common.py#L1921

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/391077

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/391077
Committed: https://git.openstack.org/cgit/openstack/keystone/commit/?id=339d6a619766d5593bf75153f25a16fd7fab79f8
Submitter: Jenkins
Branch: master

commit 339d6a619766d5593bf75153f25a16fd7fab79f8
Author: Dave Chen <email address hidden>
Date: Thu Oct 27 17:13:55 2016 +0800

    Don't deprecate the LDAP property which is still needed

    `user_attribute_ignore` or `group_attribute_ignore` are both needed
    by identity ldap backend to judge whether a specific attribute could
    be returned for read user or group operations.

    Closes-Bug: #1637135
    Change-Id: If623e1e4d3c827d00f17203652f33b74ac138d62

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/keystone 11.0.0.0b1 development milestone.