Port netapp dataontap driver to Python 3

Port netapp dataontap driver to Python 3

With this change, all unit tests on volume drivers pass on Python 3.

Changes:

* Replace a/b with a//b to get an integer on Python 3.
* Replace map(...) and filter(...) with a list-comprehension to get a
  list on Python 3.
* Replace dict.keys() with list(dict.keys()) to get a list
  on Python 3.
* Replace (str, int, float, long) with
  six.integer_types + (str, float): long type was removed
  from Python 3.
* decode_base32_to_hex(): on Python 3, decode encode_hex_to_base32()
  to return a Unicode string.
* convert_es_fmt_to_uuid(): encode/decode on Python 3 to pass the
  right types to base64.b32decode() (bytes) and uuid.UUID()
  (Unicode).
* fakes.py: Change type of XML document from Unicode to bytes: add
  b prefix to literal strings (b'...').
* Replace range(a, b) with list(range(a, b)) to get a list
  on Python 3.
* tests-py3.txt: add cinder.tests.unit.volume.drivers, all volume
  drivers tests now pass on Python 3.

Partial-Implements: blueprint cinder-python3
Change-Id: Iee609f72bbbef3789fa5e970d209047a113d005c