Description of problem:
Package python-linecache2 fails to build from source in Fedora rawhide.

+ /usr/bin/python3 -m unittest -v
linecache2.tests.test_linecache (unittest.loader._FailedTest) ... ERROR
======================================================================
ERROR: linecache2.tests.test_linecache (unittest.loader._FailedTest)
----------------------------------------------------------------------
ImportError: Failed to import test module: linecache2.tests.test_linecache
Traceback (most recent call last):
  File "/usr/lib/python3.8/unittest/loader.py", line 436, in _find_test_path
    module = self._get_module_from_name(name)
  File "/usr/lib/python3.8/unittest/loader.py", line 377, in _get_module_from_name
    __import__(name)
  File "/builddir/build/BUILD/linecache2-1.0.0/linecache2/tests/test_linecache.py", line 4, in <module>
    import unittest2 as unittest
ModuleNotFoundError: No module named 'unittest2'
----------------------------------------------------------------------

In commit https://src.fedoraproject.org/rpms/python-linecache2/c/40b3cd8b18b850cdafe787ce765021333b287e45?branch=master the dependency on unittest2 was removed, but it was pulled into the buildroot anyway, transitively. The package needs to be patched to import unittest instead of unittest2.

Version-Release number of selected component (if applicable):
1.0.0-26.fc32

Steps to Reproduce:
koji build --scratch f33 python-linecache2-1.0.0-26.fc32.src.rpm

Additional info:
This package is tracked by Koschei. See:
https://koschei.fedoraproject.org/package/python-linecache2
https://koschei.fedoraproject.org/build/8007822


This also blocks the Python 3.9 rebuild.