Remove usage of deprecated 'task_notifier' property in build_car example
Remove usage of deprecated 'task_notifier' property in build_car example

Change-Id: Ia9d18c09709d550a017c5efbe1075b9a551496f6

jimbobhickville/taskflow,junneyang/taskflow,junneyang/taskflow,jimbobhickville/taskflow,pombredanne/taskflow-1,pombredanne/taskflow-1,openstack/taskflow,openstack/taskflow