Remove py2.6 support.

python/setup.py

@@ -240,7 +240,6 @@ if __name__ == '__main__':
       classifiers=[
         "Programming Language :: Python",
         "Programming Language :: Python :: 2",
-        "Programming Language :: Python :: 2.6",
         "Programming Language :: Python :: 2.7",
         "Programming Language :: Python :: 3",
         "Programming Language :: Python :: 3.3",