[DOC] Update development cycle checklist
[DOC] Update development cycle checklist

Update the checklist for gerrit cleanup

Change-Id: Ib5b7e77c8d7d52530faa8f2e6a616a4d835d407a

bunchc/openstack-ansible,bunchc/openstack-ansible,stackforge/os-ansible-deployment,openstack/openstack-ansible,openstack/openstack-ansible,stackforge/os-ansible-deployment