Remove user creation in object service and healthcheck test

To test basic object services and healthcheck middleware it is not
required to create a test user.  By removing this code, it is now
possible to run this test without an administrator account if
allow_tenant_isolation is set to False.

Change-Id: I475e59572729a826739bedb809b8ab5bbd746861
Merge "Remove user creation in object service and healthcheck test"