Updated from global requirements

Change-Id: I080f095dd4184aed18604429519f6a930c651083
Switch to oslo.concurrency

Nova has removed nova/openstack/common/lockutils.py and switched to
oslo.concurrency so we can no longer import lockutils from the nova
tree.

Make the same switch in the ironic tree.

Closes-Bug: #1386631
Change-Id: I8db99d61dbe6c50c9edae37077242e2696bc5671
Remove duplicated _fetch_images function

This patch removes the _fetch_images function from the agent driver and
changes the driver to use the identical function found in deploy_utils.py

Change-Id: Ic206258f65a88c0f7557b405c7de425cfd01900f
Closes-Bug: 1350594
Merge "Updated from global requirements"
Merge "Remove duplicated _fetch_images function"