Remove .testr.conf
Remove .testr.conf

This commit removes .testr.conf since this repo already has
.stestr.conf. We just need .stestr.conf instead of .testr.conf.

Change-Id: Ib084dbbb4c06f57e1eb15748e992e09444cec63b

openstack/monasca-persister,openstack/monasca-persister,openstack/monasca-persister