* normalize_before_encryption(): on Python 3, unencrypted is already a Unicode
string (no need to decode).
* test_secrets: don't pass bytes string but native string (py2: bytes,
py3: Unicode) as payload
* test_secrets: Decode HTTP bytes from UTF-8 for comparison
* test_get_secret_is_decoded_for_binary(): expect a binary string,
not a Unicode string
* test_secrets: replace map() with a reglar loop (for) to execute
child.delete() on Python 3. On Python 3, map() is now lazy and only
execute the expression when the map is consumed.
* Remove tests-py3-blacklist.txt and the testenv:py34 section from
tox.ini since all unit tests now pass on Python 3.4
Partially implements: blueprint barbican-py3
Change-Id: Ief8531c3b7201f884d5d4ca7a47a381d0bb9cb2c
c5012af5f2