Updated openstack/openstack
Project: openstack/trove  072294237e84c75c15aa6b2ce54e50ada4be190e
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Add -U to pip install command in tox.ini

Ask pip to upgrade packages in the virtualenv so that a long-lived
virtualenv is still kept up to date as external dependencies change.

Change-Id: Ieae9d6f642d8ef93c699d434698c53fc1fa4e3eb