Run tests with a particular attribute
Run tests with a particular attribute

Only run tests with attr=gate for now
Add pip install numpy for performance tests in future use

Change-Id: Ifaf596394ce3a08b5abb222f1323a72673583043

stackforge/monasca-api,sapcc/monasca-api,stackforge/monasca-api,stackforge/monasca-api,sapcc/monasca-api,openstack/monasca-api,openstack/monasca-api,sapcc/monasca-api,openstack/monasca-api,stackforge/monasca-api