There were a couple of cleanups in swob as part of this. First,
status lines are always native str objects (as PEP 3333 wants), rather
than being encoded to bytes under py3. Second, _resp_body_property
now works (only) with bytestrings from the app iter.
In gatekeeper, we now deal with dict.items() returning an object of
type "dict_items" in py3, not a list. Also fixed a NameError caused by
py2's list comprehensions leaking variables to function scope where
py3's don't.
Change-Id: I6da8eceb91edb2b47aa345d61b825c7199a5569b
80858077e5