Add policy description for 'os-hide-server-addresses'
Add policy description for 'os-hide-server-addresses'

This commit adds policy doc for 'os-hide-server-addresses' policies.

Partial implement blueprint policy-docs

Change-Id: I98edbd8579f052c74283bde2ec4f85d301a0807a

openstack/nova,phenoxim/nova,Juniper/nova,openstack/nova,vmturbo/nova,jianghuaw/nova,klmitch/nova,rahulunair/nova,gooddata/openstack-nova,openstack/nova,rahulunair/nova,mahak/nova,gooddata/openstack-nova,vmturbo/nova,jianghuaw/nova,jianghuaw/nova,phenoxim/nova,mikalstill/nova,klmitch/nova,jianghuaw/nova,mikalstill/nova,gooddata/openstack-nova,Juniper/nova,gooddata/openstack-nova,vmturbo/nova,vmturbo/nova,mahak/nova,mikalstill/nova,mahak/nova,Juniper/nova,Juniper/nova,klmitch/nova,klmitch/nova,rahulunair/nova