some distros have multiple forensic files

Some Linux distributions have multiples of the files listed in the os.json, e.g., Centos has both lsb-release, and redhat-release.

I've changed the ordering somewhat in os.json so that:

* on Ubuntu machines we look at `lsb-release`, before `debian-release` which provides more information about the specific Ubuntu distro.
* on Centos machines, we look at `redhat-release` before we look at `lsb-release` which provides more information about the Centos distro.