Updated openstack/openstack
Project: openstack/nova  173200013b631f4096325a49ed075f2dc2dfcf9c

Return 404 instead of 501 for unsupported actions

Change unsupported actions return code to 404 from 501 to ensure
consistency with other unsupported actions in the REST API.

Change-Id: Ibf40ef9108f209b70ffbab6e2387d2d469f7373e