Minor change to with_python3 conditions in specfiles

[David Malcolm]

For python packages that build python 2 and 3 subpackages from one
shared src.rpm, the current example on
  http://fedoraproject.org/wiki/Packaging:Python#Example_spec_file
has this fragment:
  %if 0%{?fedora} > 12 || 0%{?rhel} > 6
  %global with_python3 1
  ...snip...
which was written with the assumption that RHEL 7 onwards will have
Python 3 packaged in the same way as we do in Fedora.

However, over the long lifetime of a RHEL release there will be multiple
upstream Python 3 releases, so RH is thinking of handling Python 3 in
RHEL 7 in a different way to how Fedora does it, to better support the
possibility of multiple Python 3 stacks - though exactly how it's to be
done in RHEL 7 isn't fleshed out yet.

Coming back to Fedora, the above means that I'd like to change the above
to omit the "rhel" clause, so that it reads:

  %if 0%{?fedora} > 12
  %global with_python3 1

and to make equivalent changes throughout the specfiles in Fedora, so
that such dual src.rpms aren't dual src.rpms in the RHEL context, only
in Fedora.

Thoughts?  Hope this sounds sane
Dave