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
- Update classifiers
- Update requirements, no need for python_version anymore
- Sync sphinx requirements with cyborg
- Update to openstack-discuss mailing list

Change-Id: I679491107a982de8c76674ec9f94162a6c961064

setup.cfg

@@ -4,8 +4,9 @@ summary = Python client for cyborg API
 description-file =
     README.rst
 author = OpenStack
-author-email = openstack-dev@lists.openstack.org
+author-email = openstack-discuss@lists.openstack.org
 home-page = https://docs.openstack.org/python-cyborgclient/latest/
+python-requires = >=3.6
 classifier =
     Environment :: OpenStack
     Intended Audience :: Information Technology
@@ -13,6 +14,8 @@ classifier =
     License :: OSI Approved :: Apache Software License
     Operating System :: POSIX :: Linux
     Programming Language :: Python
+    Programming Language :: Python :: Implementation :: CPython
+    Programming Language :: Python :: 3 :: Only
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3.6
     Programming Language :: Python :: 3.7
@@ -48,15 +51,6 @@ openstack.accelerator.v2 =
     accelerator_arq_bind = cyborgclient.osc.v2.accelerator_request:BindAcceleratorRequest
     accelerator_arq_unbind = cyborgclient.osc.v2.accelerator_request:UnbindAcceleratorRequest
 
-[build_sphinx]
-all-files = 1
-warning-is-error = 1
-source-dir = doc/source
-build-dir = doc/build
-
-[upload_sphinx]
-upload-dir = doc/build/html
-
 [compile_catalog]
 directory = cyborgclient/locale
 domain = cyborgclient

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'],
     pbr=True)

test-requirements.txt

@@ -6,8 +6,7 @@ hacking>=3.0,<3.1.0 # Apache-2.0
 
 coverage>=4.0,!=4.4 # Apache-2.0
 python-subunit>=0.0.18 # Apache-2.0/BSD
-sphinx!=1.6.6,!=1.6.7,>=1.6.2,<2.0.0;python_version=='2.7' # BSD
-sphinx!=1.6.6,!=1.6.7,!=2.1.0,>=1.6.2;python_version>='3.4' # BSD
+sphinx>=1.8.0,!=2.1.0 # BSD
 oslotest>=1.10.0 # Apache-2.0
 stestr>=1.0.0 # Apache-2.0
 testtools>=1.4.0 # MIT