This change updates the zaqar::keystone::auth class to include a default
service_name of 'zaqar' so that if a user changes the auth_name, the
service is still created as being related to 'zaqar'. This improves the
user experiance when they want to customize the usernames for services.
Change-Id: I2977790c3558732c2a1773aa3ede834c1d62ca16
Closes-Bug: #1590040