Add OpenStack trove classifier for PyPI

Add trove classifier to have the client listed among the
other OpenStack-related projets on PyPI.

Change-Id: I1ddae8d1272a2b1c5e4c666c9aa4e4a274431415
Signed-off-by: Doug Hellmann <doug.hellmann@dreamhost.com>

setup.py

@@ -25,6 +25,7 @@ setuptools.setup(
     classifiers=[
         'Development Status :: 4 - Beta',
         'Environment :: Console',
+        'Environment :: OpenStack',
         'Intended Audience :: Developers',
         'Intended Audience :: Information Technology',
         'License :: OSI Approved :: Apache Software License',