Port zonemanager to Python 3

Port zonemanager to Python 3

* Replace xrange() with six.moves.range()
* Replace filter() with list-comprehension to get a list on Python 3.
* get_formatted_wwn(): join byte strings with b':' instead of ':'
* ZoneManager: don't pass arguments to object.__new__()
* tests-py3.txt: add zonemanager tests

Partial-Implements: blueprint cinder-python3
Change-Id: Ia3fcd816c5afd7a08b8769fbc9d2839b70c8c3fb