Replace Conflicts python2-flask with Obsoletes and specify epoch

Resolves https://bugzilla.redhat.com/show_bug.cgi?id=1767198

The problem was:

Error: Transaction check error:
  file /usr/bin/flask from install of python3-flask-1:1.0.2-8.fc32.noarch
  conflicts with file from package python2-flask-1:1.0.2-6.fc31.noarch

That problem is caused by the missing epoch.
However even when adding the epoch, there would be an error with an explicit conflict
and python2-flask would need to be obsoleted via fedora-obsolete-packages.
We save ourselves some coordination trouble and obsolete the package from python3-flask,
despite arguably, some people might not like that as python3-flask
does not, by some definitions, "replace" python2-flask.
However, such definitions are hard to express.

python-flask.spec

@@ -3,7 +3,7 @@
 
 Name:           python-%{modname}
 Version:        1.0.2
-Release:        8%{?dist}
+Release:        9%{?dist}
 Epoch:          1
 Summary:        A micro-framework for Python based on Werkzeug, Jinja 2 and good intentions
 
@@ -39,7 +39,7 @@ Requires:       python%{python3_pkgversion}-jinja2
 Requires:       python%{python3_pkgversion}-werkzeug
 Requires:       python%{python3_pkgversion}-itsdangerous
 Requires:       python%{python3_pkgversion}-click
-Conflicts:      python2-%{modname} < 1.0.2-8
+Obsoletes:      python2-%{modname} < 1:1.0.2-9
 
 %description -n python%{python3_pkgversion}-%{modname} %{_description}
 
@@ -84,6 +84,9 @@ PYTHONPATH=%{buildroot}%{python3_sitelib} py.test-%{python3_version} -v -k "not
 %doc examples
 
 %changelog
+* Wed Oct 30 2019 Miro Hrončok <mhroncok@redhat.com> - 1:1.0.2-9
+- Obsolete proper version of python2-flask to fix an upgrade path issue (#1767198)
+
 * Wed Sep 18 2019 Miro Hrončok <mhroncok@redhat.com> - 1:1.0.2-8
 - Subpackage python2-flask has been removed
   See https://fedoraproject.org/wiki/Changes/Mass_Python_2_Package_Removal