Add OpenStack trove classifier for PyPI

Add trove classifier to have swift listed among the
other OpenStack-related projets on PyPI to reserve
the name, even though we won't release packages there.

Change-Id: I2c6cd2e37ea55d2bc2ddbba813ee2a190b1c90a9
Signed-off-by: Doug Hellmann <doug.hellmann@dreamhost.com>

setup.py

@@ -38,6 +38,7 @@ setup(
         'Operating System :: POSIX :: Linux',
         'Programming Language :: Python :: 2.6',
         'Environment :: No Input/Output (Daemon)',
+        'Environment :: OpenStack',
     ],
     install_requires=[],  # removed for better compat
     scripts=[