Currently, if a single lookup call to the Ironic API fails, the entire
agent errors out and restarts. This allows the agent to retry for a set
amount of time before throwing an uncaught exception forcing a restart.
Change-Id: I39752fb3f42ad3e4f15a49194f1554e1d3463cf8
Closes-Bug: 1297019
Allow multiple extensions to be loaded by switching to ExtensionManager
from stevedore. Remove any reference to modes.
Change-Id: Ic160478625226b4dd17bd68b3d37f3b05823e519