Implement execute_service_step() in AgentBaseMixin that will
asynchronously execute service step on the agent. Without it, Ironic
will try to find <step_name> attribute on the object that implements
interface specified by the servicing step.
Example:
Step: [{"interface": "deploy", "step": "burnin_cpu"}]
Error: AttributeError: 'AgentDeploy' object has no attribute 'burnin_cpu'
Closes-Bug: #2069430
Change-Id: Idb1d5b50656c3765ea5c9e21b7844946ae4cfc67
Signed-off-by: Przemyslaw Szczerbik <przemyslaw.szczerbik@intel.com>
4f924f2d64