subunit-1.1.0-3.fc24 fails to build in F24 because tests crash:

make -C perl check
make[2]: Entering directory '/builddir/build/BUILD/subunit-1.1.0/perl'
make[2]: Nothing to be done for 'check'.
make[2]: Leaving directory '/builddir/build/BUILD/subunit-1.1.0/perl'
SHELL_SHARE='./shell/share/' \
PYTHONPATH='/builddir/build/BUILD/subunit-1.1.0/python':'/builddir/build/BUILD/subunit-1.1.0':/builddir/build/BUILD/subunit-1.1.0/python/subunit:/builddir/build/BUILD/subunit-1.1.0/python/subunit/tests \
/usr/bin/python -m testtools.run all_tests.test_suite
Tests running...
Ran 52 tests in 0.008s
OK
Traceback (most recent call last):
  File "/usr/lib/python2.7/runpy.py", line 162, in _run_module_as_main
    "__main__", fname, loader, pkg_name)
  File "/usr/lib/python2.7/runpy.py", line 72, in _run_code
    exec code in run_globals
  File "/usr/lib/python2.7/site-packages/testtools/run.py", line 267, in <module>
    main(sys.argv, sys.stdout)
  File "/usr/lib/python2.7/site-packages/testtools/run.py", line 264, in main
    stdout=stdout)
  File "/usr/lib/python2.7/site-packages/testtools/run.py", line 187, in __init__
    self.runTests()
  File "/usr/lib/python2.7/site-packages/testtools/run.py", line 221, in runTests
    self.result = testRunner.run(self.test)
  File "/usr/lib/python2.7/site-packages/testtools/run.py", line 107, in run
    return test.run(result)
  File "/usr/lib/python2.7/site-packages/unittest2/suite.py", line 126, in run
    test(result)
  File "/usr/lib/python2.7/unittest/suite.py", line 70, in __call__
    return self.run(*args, **kwds)
  File "/usr/lib/python2.7/unittest/suite.py", line 108, in run
    test(result)
  File "/usr/lib/python2.7/unittest/suite.py", line 70, in __call__
    return self.run(*args, **kwds)
  File "/usr/lib/python2.7/unittest/suite.py", line 108, in run
    test(result)
  File "/usr/lib/python2.7/unittest/suite.py", line 70, in __call__
    return self.run(*args, **kwds)
  File "/usr/lib/python2.7/unittest/suite.py", line 108, in run
    test(result)
  File "/usr/lib/python2.7/unittest/suite.py", line 70, in __call__
    return self.run(*args, **kwds)
  File "/usr/lib/python2.7/unittest/suite.py", line 108, in run
    test(result)
  File "/usr/lib/python2.7/site-packages/unittest2/case.py", line 649, in __call__
    return self.run(*args, **kwds)
  File "/usr/lib/python2.7/site-packages/testtools/testcase.py", line 606, in run
    return run_test.run(result)
  File "/usr/lib/python2.7/site-packages/testtools/runtest.py", line 80, in run
    return self._run_one(actual_result)
  File "/usr/lib/python2.7/site-packages/testtools/runtest.py", line 94, in _run_one
    return self._run_prepared_result(ExtendedToOriginalDecorator(result))
  File "/usr/lib/python2.7/site-packages/testtools/runtest.py", line 108, in _run_prepared_result
    self._run_core()
  File "/usr/lib/python2.7/site-packages/testtools/runtest.py", line 144, in _run_core
    self.case._run_test_method, self.result):
  File "/usr/lib/python2.7/site-packages/testtools/runtest.py", line 193, in _run_user
    return self._got_user_exception(sys.exc_info())
  File "/usr/lib/python2.7/site-packages/testtools/runtest.py", line 213, in _got_user_exception
    self.case.onException(exc_info, tb_label=tb_label)
  File "/usr/lib/python2.7/site-packages/testtools/testcase.py", line 556, in onException
    self._report_traceback(exc_info, tb_label=tb_label)
  File "/usr/lib/python2.7/site-packages/testtools/testcase.py", line 592, in _report_traceback
    self, '__testtools_tb_locals__', False)))
  File "/usr/lib/python2.7/site-packages/testtools/content.py", line 204, in __init__
    stack_lines = list(traceback.TracebackException(exctype, value, tb,
AttributeError: 'NoneType' object has no attribute 'TracebackException'
Makefile:1153: recipe for target 'check-local' failed

Difference between working and failing build root:

        python3-testtools 	1.5.0-2.fc23 	> 	1.8.0-1.fc24
	python-testtools 	1.5.0-2.fc23 	> 	1.8.0-1.fc24
	glibc 	2.21.90-19.fc24 	> 	2.21.90-20.fc24
	python-pbr 		> 	1.3.0-1.fc24
	python3-pbr 		> 	1.3.0-1.fc24
	glibc-common 	2.21.90-19.fc24 	> 	2.21.90-20.fc24
	sqlite 	3.8.10.2-3.fc23 	> 	3.8.11-1.fc24
	glibc-devel 	2.21.90-19.fc24 	> 	2.21.90-20.fc24
	kernel-headers 	4.2.0-0.rc3.git4.1.... 	> 	4.2.0-0.rc4.git0.1....
	glibc-headers 	2.21.90-19.fc24 	> 	2.21.90-20.fc24