Explain obj_to_dict
Explain obj_to_dict

It's entirely possile that the reason for the existence of this function
may not be immediately apparent.

Change-Id: Ia6839740d676ca99d919af732ede3a5982f5d864

openstack-infra/shade,openstack/python-openstacksdk,openstack/python-openstacksdk,openstack-infra/shade,stackforge/python-openstacksdk,dtroyer/python-openstacksdk,jsmartin/shade,jsmartin/shade,dtroyer/python-openstacksdk,stackforge/python-openstacksdk