Test data is not included in the pypi tarball

[mgorny]

When attempting to run tests from the pypi tarball, they fail due to missing files:

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ERROR: test_bugzilla_16 (tests.test_7zfiles.Test7ZipFiles)
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Traceback (most recent call last):
  File "tests/test_7zfiles.py", line 212, in test_bugzilla_16
    fp = self._open_file(os.path.join(ROOT, 'data', 'bugzilla_16.7z'), 'rb')
  File "tests/test_7zfiles.py", line 67, in _open_file
    fp = open(filename, mode)
IOError: [Errno 2] No such file or directory: '/tmp/portage/dev-python/pylzma-0.4.9/work/pylzma-0.4.9/tests/data/bugzilla_16.7z'

======================================================================
ERROR: test_bugzilla_4 (tests.test_7zfiles.Test7ZipFiles)
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Traceback (most recent call last):
  File "tests/test_7zfiles.py", line 130, in test_bugzilla_4
    fp = self._open_file(os.path.join(ROOT, 'data', 'bugzilla_4.7z'), 'rb')
  File "tests/test_7zfiles.py", line 67, in _open_file
    fp = open(filename, mode)
IOError: [Errno 2] No such file or directory: '/tmp/portage/dev-python/pylzma-0.4.9/work/pylzma-0.4.9/tests/data/bugzilla_4.7z'

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