Updated openstack/openstack
Project: openstack/nova  846fcb3b1618ab22ab23af5fc43aed6e92dbea36

Add missing create() method on SecurityGroupRule object

The nova.objects.SecurityGroupRule class was missing the
create() method, so we add it here, and while doing so,
ensure that the id attribute is marked as read-only.

Partial-Blueprint: compute-manager-objects-juno
Change-Id: I4584e33d9d163a7dce01b01d205f2f43824e544f