The reality is that "stable" is what is tested. This tries to give
enough info that users can ascertain what tests are running at any
given time and hence what elements are known to be working.
Additional, clarify the Fedora position in the README as now described
by above.
Closes: #1653561
Change-Id: Ifb91b9089790897861bd7e671c3dba59adac239d