Make _test_update_resource honor format
Make _test_update_resource honor format

Closes-Bug: #1217759

Partial-Bug: #1217791
Due to the Related-Bug: #1217791, MyComparator does not work
in some cases. We need to use a workaround that serialized body
to mocked self.client.httpclient.request. It is already adopted
in _test_create_resourse and I borrow it.

Change-Id: I746d272bc7ba8542c29e47823f707a761dddb0b1

asadoughi/python-neutronclient,johnpbatty/python-neutronclient,roaet/python-neutronclient,openstack/python-neutronclient,roaet/python-neutronclient,ntt-sic/python-neutronclient,NeCTAR-RC/python-neutronclient,mangelajo/python-neutronclient,varunarya10/python-neutronclient,rackerlabs/rackspace-python-neutronclient,vijayendrabvs/ssl-python-neutronclient,asadoughi/python-neutronclient,cernops/python-neutronclient,venusource/python-neutronclient,ntt-sic/python-neutronclient,eayunstack/python-neutronclient,venusource/python-neutronclient,Juniper/python-neutronclient,mangelajo/python-neutronclient,yamahata/python-tackerclient,huntxu/python-neutronclient,eayunstack/python-neutronclient,NeCTAR-RC/python-neutronclient,JioCloud/python-neutronclient,sajuptpm/python-neutronclient-ipam,citrix-openstack-build/python-neutronclient,varunarya10/python-neutronclient,citrix-openstack-build/python-neutronclient,openstack/python-neutronclient,noironetworks/python-neutronclient,cernops/python-neutronclient,johnpbatty/python-neutronclient,Stavitsky/python-neutronclient,rackerlabs/rackspace-python-neutronclient,cryptickp/python-neutronclient,vichoward/python-neutronclient,JioCloud/python-neutronclient,vichoward/python-neutronclient,yamahata/python-tackerclient,Juniper/python-neutronclient,cryptickp/python-neutronclient,Stavitsky/python-neutronclient,vijayendrabvs/ssl-python-neutronclient,sajuptpm/python-neutronclient-ipam,huntxu/python-neutronclient,noironetworks/python-neutronclient