py33: use six.iteritems for item iterations (part2)

Second final part of replacement dict.iteritems() with
six.iteritems(dict)

Partially-implements blueprint py3-compatibility

Change-Id: I2c4f23a8ba2defcebb0dacf04cdad9f1dc40c04e
Merge "py33: use six.iteritems for item iterations (part2)"