Capture logs when running unit tests
Capture logs when running unit tests

The unit test logs are mixed up in the output of subunit-trace.
Adding OS_LOG_CAPTURE=1 by default to avoid that.

Change-Id: Ie322795c8638963b276c4bd54b845331c3567370

masayukig/tempest,masayukig/tempest,openstack/tempest,openstack/tempest,cisco-openstack/tempest,Juniper/tempest,Juniper/tempest,cisco-openstack/tempest