Sync latest openstack-common.

This fixes an issue when trying to run install_venv from within
the source directory.

Change-Id: Id4dcb070319ec52d0a1b466e911fbfdf805db613
Update .coveragerc

Set up proper source and omit options.

Change-Id: Ia067d229eb3d7a5806364de22724c16166950bc1
Implements: blueprint update-coveragerc
Merge "Sync latest openstack-common."
Merge "Update .coveragerc"