Remove references to Python 2.7

We don't support it anymore. This is just noise now.

Change-Id: I3640e7d8e520db69f83f95e9c7759279f7c15008
Signed-off-by: Stephen Finucane <sfinucan@redhat.com>

Author: stephenfin

HACKING.rst

@@ -7,6 +7,7 @@ OpenStack Style Commandments
 
 General
 -------
+
 - thou shalt not violate causality in our time cone, or else
 
 Docstrings
@@ -85,23 +86,3 @@ commandline arguments, etc.) should be presumed to be encoded as utf-8.
     returntext = do_some_magic_with(mytext)
     returnstring = returntext.encode('utf-8')
     outfile.write(returnstring)
-
-Python 3.x Compatibility
-------------------------
-
-OpenStackClient strives to be Python 3.3 compatible.  Common guidelines:
-
-* Convert print statements to functions: print statements should be converted
-  to an appropriate log or other output mechanism.
-* Prefer to x.items() over six.iteritems(x).
-
-Running Tests
--------------
-
-Note: Oh boy, are we behind on writing tests.  But they are coming!
-
-The testing system is based on a combination of tox and testr. If you just
-want to run the whole suite, run `tox` and all will be fine. However, if
-you'd like to dig in a bit more, you might want to learn some things about
-testr itself. A basic walkthrough for OpenStack can be found at
-http://wiki.openstack.org/testr

doc/source/contributor/developing.rst

@@ -59,13 +59,13 @@ To run the full suite of tests maintained within OpenStackClient.
     virtualenvs. You can later use the ``-r`` option with ``tox`` to rebuild
     your virtualenv in a similar manner.
 
-
-To run tests for one or more specific test environments(for example, the most common configuration of
-Python 2.7 and PEP-8), list the environments with the ``-e`` option, separated by spaces:
+To run tests for one or more specific test environments(for example, the most
+common configuration of the latest Python version and PEP-8), list the
+environments with the ``-e`` option, separated by spaces:
 
 .. code-block:: bash
 
-    $ tox -e py27,pep8
+    $ tox -e py38,pep8
 
 See ``tox.ini`` for the full list of available test environments.
 
@@ -96,9 +96,9 @@ Using PDB breakpoints with ``tox`` and ``testr`` normally does not work since
 the tests fail with a `BdbQuit` exception rather than stopping at the
 breakpoint.
 
-To run with PDB breakpoints during testing, use the `debug` ``tox`` environment
-rather than ``py27``. For example, passing a test name since you will normally
-only want to run the test that hits your breakpoint:
+To run with PDB breakpoints during testing, use the ``debug`` ``tox``
+environment. For example, passing a test name since you will normally only want
+to run the test that hits your breakpoint:
 
 .. code-block:: bash
 
@@ -207,4 +207,3 @@ Example
     from openstackclient import shell
     from openstackclient.tests import utils
     from unittest import mock
-