selinux config - no warning during upgrades

[Bruno Wolff III]

I recently did a yum upgrade from Fedora Core 5 to Rawhide and afterwards
I eventually noticed that I was getting warnings about a NULL security
context. I then tracked this down to not having a proper selinux user
configuration.

Since I was using the default, I expected things would work or at least that
there would be *.rpmnew files that acted as a hint that something needed
to be looked at. Also, in order to find out what the default was I ended up
looking at some other machines that had more recent installs, because there
didn't seem to be any obvious place to look on the affected machine for
what reasonable default values were.