Add some test-cases for cinder cli

Add some omitted test-cases for cinder-cli in tempest

 + test_cinder_credentials
 + test_cinder_availability_zone_list
 + test_cinder_endpoints
 + test_cinder_service_list
 + test_cinder_transfer_list
 + test_cinder_bash_completion

Change-Id: I2d05fa0fb1421c292097c19643ed22f221a0d349
Merge "Add some test-cases for cinder cli"