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 sections from setup.cfg:
  * Wheel is not needed for python 3 only repo
  * Some other sections are obsolete
- Update classifiers
- Update requirements, no need for python_version anymore

Change-Id: I1251a9904fcc146ec615ba2c7f93a1b675e3220f

setup.cfg

@@ -6,6 +6,7 @@ description-file =
 author = OpenStack
 author-email = openstack-discuss@lists.openstack.org
 home-page = https://docs.openstack.org/pymod2pkg/latest/
+python-requires = >=3.6
 classifier =
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3.6
@@ -16,10 +17,6 @@ classifier =
     Topic :: Software Development :: Libraries
     Topic :: Utilities
 
-[global]
-setup-hooks =
-    pbr.hooks.setup_hook
-
 [entry_points]
 console_scripts =
     pymod2pkg = pymod2pkg:main
@@ -27,14 +24,3 @@ console_scripts =
 [files]
 packages =
     pymod2pkg
-
-[build_sphinx]
-all_files = 1
-source-dir = doc/source
-build-dir = doc/build
-
-[upload_sphinx]
-upload-dir = doc/build/html
-
-[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)

test-requirements.txt

@@ -5,5 +5,5 @@ stestr>=2.0.0 # Apache-2.0
 testresources>=2.0.0 # Apache-2.0/BSD
 testtools>=2.2.0 # MIT
 
-sphinx!=1.6.6,!=1.6.7;python_version>='3.4'  # BSD
+sphinx>=1.6.1,!=1.6.6,!=1.6.7 # BSD
 openstackdocstheme>=1.18.1 # Apache-2.0