Trivial: Update pypi url to new url
Trivial: Update pypi url to new url

Pypi url changed from [1] to [2]

[1] https://pypi.python.org/pypi/<package>
[2] https://pypi.org/project/<package>

Change-Id: I1d9424b280623d3de16ff239872bfeb8ebe60fc3

openstack/oslo.middleware