Fix and unify cover environment
Fix and unify cover environment

Fix cover environment and unify it accordingly to Project Testing
Interface [1].

[1] https://governance.openstack.org/tc/reference/pti/python.html#coverage-jobs

Change-Id: I9cde2c00785596f3971378520cbc0ea96e141ac1

stackforge/monasca-log-api,openstack/monasca-log-api,stackforge/monasca-log-api,stackforge/monasca-log-api,openstack/monasca-log-api,openstack/monasca-log-api