Switch test config file to use os_region_name
Switch test config file to use os_region_name

The old value of nova_region_name has not been used in some time.

Change-Id: I8fdd6d8ae4f0982b37cff7b5583429ccb6bd4aaf

openstack/trove,hplustree/trove,mmasaki/trove,openstack/trove,mmasaki/trove,zhangg/trove,mmasaki/trove,hplustree/trove,zhangg/trove