This improves on commit 4350c176048b8d159d08b82b915e9544ac9dee6f

We found a major performance regression in keystoneclient
when using PKI tokens, related to http://bugs.python.org/issue25870

It can be tested with
time python -c "import textwrap; textwrap.wrap('x'*9000, 64)"

which has a complexity of O(n*n)
because it uses certain regexps in python versions before 3.5.

Closes-Bug: #1526686
Related-Bug: #1404402

Change-Id: Ibc81907c4d9db2c09fff41ccf21345fbdb19202d

We are removing Python 2.6 support from the Keystone libraries.

Change-Id: I1c7a79edd41a73946c9d77bfb8cd2075e2500760
Closes-Bug: 1519449

Recently, the error message in _process_communicate_handle_oserror()
has been i18n'ed, which caused the regression as another code path
appended a string to it, which causes the TypeError to be raised.

Fix it by using string formatting instead of '+' to force it
to convert to string before concatenating.

Closes-Bug: 1421652

Change-Id: I7229b46888f798ac4a69c140ab389afed49b8c3c

is_ans1_token wasn't properly deprecated since it used LOG.warn
rather than warnings/debtcollector. Proper deprecation requires use
of warnings and documentation.

bp deprecations

Change-Id: I81be2844014745a5951ce91a336e9e9ecf4d5328

A comment on a function doesn't deprecate it since users aren't
going to see it.

The removed deprecation comment is doubly useless since this
function can't be deprecated. There's no alternative given and it's
actively used by keystonemiddleware.

bp deprecations

Change-Id: Ib9bf1b6e0631423094ebe60ff2a718dd659b5561

More details by the code author in his blog post at
http://adam.younglogic.com/2014/02/compressed-tokens/.

Change-Id: I35c5eca2e04a74236bd8c7fb6daab3ea46b59b0e
Closes-Bug: #1352314

Change-Id: I5bd4f46b34f0bbb21f1b6a6bfeeb2a26f5544156