Add 0.17 marker to README.rst
Add 0.17 marker to README.rst

Change-Id: Ia27a68f94938aa1d7162de5a643b034cf9c5f4e6

openstack/openstack-doc-tools,savinash47/openstack-doc-tools,openstack/openstack-doc-tools,savinash47/openstack-doc-tools,savinash47/openstack-doc-tools