Add description to policies in certificates.py
Add description to policies in certificates.py

Change-Id: I6eb0881d378e286e36b4cd04c494409612ee152e
blueprint: policy-docs

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