Pin unittest-xml-reporting in development requirements

traceback in Jenkins was

raceback (most recent call last):
16:56:43    File "manage.py", line 10, in <module>
16:56:43      execute_from_command_line(sys.argv)
16:56:43    File "/var/lib/jenkins/venvs/700f057c5e2a833963b94f4cff2d99c057b62d7619639d041a6d0dd26644123e/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 354, in execute_from_command_line
16:56:43      utility.execute()
16:56:43    File "/var/lib/jenkins/venvs/700f057c5e2a833963b94f4cff2d99c057b62d7619639d041a6d0dd26644123e/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 346, in execute
16:56:43      self.fetch_command(subcommand).run_from_argv(self.argv)
16:56:43    File "/var/lib/jenkins/venvs/700f057c5e2a833963b94f4cff2d99c057b62d7619639d041a6d0dd26644123e/local/lib/python2.7/site-packages/django/core/management/commands/test.py", line 30, in run_from_argv
16:56:43      super(Command, self).run_from_argv(argv)
16:56:43    File "/var/lib/jenkins/venvs/700f057c5e2a833963b94f4cff2d99c057b62d7619639d041a6d0dd26644123e/local/lib/python2.7/site-packages/django/core/management/base.py", line 394, in run_from_argv
16:56:43      self.execute(*args, **cmd_options)
16:56:43    File "/var/lib/jenkins/venvs/700f057c5e2a833963b94f4cff2d99c057b62d7619639d041a6d0dd26644123e/local/lib/python2.7/site-packages/django/core/management/commands/test.py", line 74, in execute
16:56:43      super(Command, self).execute(*args, **options)
16:56:43    File "/var/lib/jenkins/venvs/700f057c5e2a833963b94f4cff2d99c057b62d7619639d041a6d0dd26644123e/local/lib/python2.7/site-packages/django/core/management/base.py", line 445, in execute
16:56:43      output = self.handle(*args, **options)
16:56:43    File "/var/lib/jenkins/venvs/700f057c5e2a833963b94f4cff2d99c057b62d7619639d041a6d0dd26644123e/local/lib/python2.7/site-packages/django/core/management/commands/test.py", line 90, in handle
16:56:43      failures = test_runner.run_tests(test_labels)
16:56:43    File "/var/lib/jenkins/venvs/700f057c5e2a833963b94f4cff2d99c057b62d7619639d041a6d0dd26644123e/local/lib/python2.7/site-packages/django/test/runner.py", line 211, in run_tests
16:56:43      result = self.run_suite(suite)
16:56:43    File "/var/lib/jenkins/venvs/700f057c5e2a833963b94f4cff2d99c057b62d7619639d041a6d0dd26644123e/local/lib/python2.7/site-packages/xmlrunner/extra/djangotestrunner.py", line 58, in run_suite
16:56:43      results = runner.run(suite)
16:56:43    File "/var/lib/jenkins/venvs/700f057c5e2a833963b94f4cff2d99c057b62d7619639d041a6d0dd26644123e/local/lib/python2.7/site-packages/xmlrunner/runner.py", line 70, in run
16:56:43      test(result)
16:56:43    File "/usr/lib/python2.7/unittest/suite.py", line 70, in __call__
16:56:43      return self.run(*args, **kwds)
16:56:43    File "/usr/lib/python2.7/unittest/suite.py", line 108, in run
16:56:43      test(result)
16:56:43    File "/var/lib/jenkins/venvs/700f057c5e2a833963b94f4cff2d99c057b62d7619639d041a6d0dd26644123e/local/lib/python2.7/site-packages/django/test/testcases.py", line 186, in __call__
16:56:43      super(SimpleTestCase, self).__call__(result)
16:56:43    File "/usr/lib/python2.7/unittest/case.py", line 393, in __call__
16:56:43      return self.run(*args, **kwds)
16:56:43    File "/usr/lib/python2.7/unittest/case.py", line 304, in run
16:56:43      result.startTest(self)
16:56:43    File "/var/lib/jenkins/venvs/700f057c5e2a833963b94f4cff2d99c057b62d7619639d041a6d0dd26644123e/local/lib/python2.7/site-packages/xmlrunner/result.py", line 273, in startTest
16:56:43      _, self.lineno = inspect.getsourcelines(test_method)
16:56:43    File "/usr/lib/python2.7/inspect.py", line 690, in getsourcelines
16:56:43      lines, lnum = findsource(object)
16:56:43    File "/usr/lib/python2.7/inspect.py", line 538, in findsource
16:56:43      raise IOError('could not get source code')
16:56:43  IOError: could not get source code

.jenkins/Jenkinsfile

@@ -59,7 +59,6 @@ pipeline {
             then
               virtualenv ${venv_path}
               ${activate_venv}
-              pip install unittest-xml-reporting
               pip install -r extra/requirements/development.txt
             fi
             """

extra/requirements/development.txt

@@ -14,3 +14,4 @@ responses==0.8.1
 selenium==3.6.0
 sphinx-rtd-theme==0.2.4
 Sphinx==1.6.5
+unittest-xml-reporting==2.3.2