@Wayne-Workman I don’t happen to have a vm template of centos 6 any more, but I can spin up a new vm tonight with centos 6 on it and test.
BUT my recommendation to the OP (for what ever its worth), if they have a virtualization environment I would spin up a new Centos 7 vm and then install 1.3.0-rc2 on it clean. Yes that will mean that they will have to recreate the FOG environment all over, a lot can be done by copy and pasting and then transferring the /images directory over. So it will be some work to do. BUT what it will give you is a fall back system in case of difficulties with the new version of FOG. If the new FOG server falls down the old one is still there, all you need to do is power it on.
With that said, I can spin up a new centos 6 vm tonight and see if fog 1.3.0-rc2 installs without any monkey business. Understand this will not be an exact match for the OPs environment since the OP is upgrading fog from 0.30.