* Replace dict.iteritems() and six.iteritems(dict) with dict.items()
* Replace "for key in dict.iterkeys():" with "for key in dict:"
For readability, it was decided to use the dict.items() even on
Python 2, instead of six.iteritems(dict). The performance overhead
(creation of a temporary list) is negligible.
Change-Id: I56bcea5302c07448b527784731b40ebe8642433e
1f4fa2b6e4