1. What is the problem?
Using tempest plugin in conjuction with
NEUTRON_CREATE_INITIAL_NETWORKS to set False was causing failures
during the execution of the stack.sh script. This issue was solved
in I62e74d350d6533fa842d64c15b01b1a3d42c71c2 but it hasn't reflected
on the devstack samples.
2. What is the solution to the problem?
Let the users to enable or disable the tempest usage on their devstack
environments.
3. What the features need to be implemented to the Tricircle to
realize the solution?
No new features
Change-Id: Iad563a660ea58faa57984ee7829ee45e5811c900