Cleanup py27 support

Make a few cleanups:
- Remove python 2.7 stanza from setup.py
- Add requires on python >= 3.6 to setup.cfg so that pypi and pip
  know about the requirement
- Remove obsolete section from setup.cfg: Wheel is not needed for
  python 3 only repo
- Update requirements, no need for python_version anymore
- Remove future import from doc/source/conf.py

Change-Id: Ibf594171cea8f81cc4139b29cbdce54f6d5107a7

doc/source/conf.py

@@ -10,8 +10,6 @@
 # All configuration values have a default; values that are commented out
 # serve to show the default.
 
-from __future__ import unicode_literals
-
 import os
 import sys
 

setup.cfg

@@ -6,6 +6,7 @@ description-file =
 author = OpenStack
 author-email = openstack-discuss@lists.openstack.org
 home-page = https://docs.openstack.org/python-keystoneclient/latest/
+python-requires = >=3.6
 classifier =
     Environment :: OpenStack
     Intended Audience :: Information Technology
@@ -35,21 +36,12 @@ keystoneclient.auth.plugin =
     v3scopedsaml = keystoneclient.contrib.auth.v3.saml2:Saml2ScopedToken
     v3unscopedadfs = keystoneclient.contrib.auth.v3.saml2:ADFSUnscopedToken
 
-[build_sphinx]
-source-dir = doc/source
-build-dir = doc/build
-all_files = 1
-warning-is-error = 1
-
 [pbr]
 autodoc_tree_index_modules = True
 autodoc_tree_excludes =
   setup.py
   keystoneclient/tests/
 
-[upload_sphinx]
-upload-dir = doc/build/html
-
 [compile_catalog]
 directory = keystoneclient/locale
 domain = keystoneclient
@@ -63,6 +55,3 @@ input_file = keystoneclient/locale/keystoneclient.pot
 keywords = _ gettext ngettext l_ lazy_gettext
 mapping_file = babel.cfg
 output_file = keystoneclient/locale/keystoneclient.pot
-
-[wheel]
-universal = 1

setup.py

@@ -13,17 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# THIS FILE IS MANAGED BY THE GLOBAL REQUIREMENTS REPO - DO NOT EDIT
 import setuptools
 
-# In python < 2.7.4, a lazy loading of package `pbr` will break
-# setuptools if some other modules registered functions in `atexit`.
-# solution from: http://bugs.python.org/issue15881#msg170215
-try:
-    import multiprocessing  # noqa
-except ImportError:
-    pass
-
 setuptools.setup(
     setup_requires=['pbr>=2.0.0'],
     pbr=True)