Add rfc.sh to help with gerrit workflow.
Add rfc.sh to help with gerrit workflow.

Change-Id: Ida3c5cd3f10d776890f3f50bf18c8e5d2817c391

zancas/hacking,emonty/oslo-hacking,zancas/hacking,openstack-dev/hacking,hyakuhei/cleantox,emonty/oslo-hacking,openstack-dev/hacking,hyakuhei/cleantox