Updated openstack/openstack
Project: openstack/heat  58e141b2aceb807b3fe8c8f6fa8ce3da624d05ef

replace dict.iteritems() with six.iteritems(dict)

According to https://wiki.openstack.org/wiki/Python3 dict.iteritems()
should be replaced with six.iteritems(dict).

Change-Id: I9e2881a006433c8b44a3caccebc73bae4973a041