Update link to stable branch policy page
Update link to stable branch policy page

On docs bugs policies page link to page which
describes OpenStack stable branch policy is updated to
correct page.

Change-Id: I4eb4a53c52155da4abcf724885339df2afecdfaf

openstack/neutron,openstack/neutron,mahak/neutron,eayunstack/neutron,huntxu/neutron,mahak/neutron,eayunstack/neutron,huntxu/neutron,openstack/neutron,noironetworks/neutron,noironetworks/neutron,mahak/neutron