Use uuidutils instead of uuid.uuid4()
Use uuidutils instead of uuid.uuid4()

Openstack common has a wrapper for generating uuids.
We should only use that function when generating
uuids for consistency.

Change-Id: Iadd98fd145e7f0a37c953936feaf69bd3527000f
Closes-Bug: #1082248

NaohiroTamura/python-ironicclient,NaohiroTamura/python-ironicclient,openstack/python-ironicclient,openstack/python-ironicclient