'Prepares prop_diff values for correct neutron update call.
1. Merges value_specs
2. Defaults resource name to physical resource name if None'

def prepare_update_properties(self, prop_diff):

    if (('value_specs' in prop_diff) and prop_diff['value_specs']):
        NeutronResource.merge_value_specs(prop_diff)
    if (('name' in prop_diff) and (prop_diff['name'] is None)):
        prop_diff['name'] = self.physical_resource_name()
