Fix packaging of 2.1.0 in Fedora: testing requires "pytest-timeout".

[Romain-Geissler-1A]

Without this, we get this in the Fedora package when trying to upgrade to 2.1.0:

+ /usr/bin/pytest --ignore=test/test_consumer_integration.py --ignore=test/record/test_util.py test
ERROR: usage: pytest [options] [file_or_dir] [file_or_dir] [...]
pytest: error: unrecognized arguments: --timeout=300
  inifile: /builddir/build/BUILD/python-kafka-2.1.0-build/kafka-python-2.1.0/pytest.ini
  rootdir: /builddir/build/BUILD/python-kafka-2.1.0-build/kafka-python-2.1.0

Fedora update pull request submitted here: https://src.fedoraproject.org/rpms/python-kafka/pull-request/5

[dpkp]

Thanks!