Fix image create functions for Ironic

This fixes an issue where --container-format was not passed to
'openstack image create'.

Change-Id: If1431c8dc8ff8e940f99e984939f5b2732bb0ee0
Closes-Bug: 1357495
Add ironic-python-agent support to devstack

This adds support for using ironic-python-agent with Ironic.

Change-Id: I8f1e93e09ddde447996ecbedceb091f51d60040e