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
- Update classifiers
- Update requirements, no need for python_version anymore

Change-Id: I2f4d7644588316c30e639dcb093c5638b5b5526c

doc/requirements.txt

@@ -2,8 +2,7 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 
-sphinx>=1.6.2,!=1.6.6,!=1.6.7,<2.0.0;python_version=='2.7'  # BSD
+sphinx>=1.6.2,!=1.6.6,!=1.6.7,!=2.1.0 # BSD
-sphinx>=1.6.2,!=1.6.6,!=1.6.7,!=2.1.0;python_version>='3.4'  # BSD
 openstackdocstheme>=1.20.0 # Apache-2.0
 
 # releasenotes

setup.cfg

@@ -6,6 +6,7 @@ description-file =
 author = OpenStack
 author-email = openstack-discuss@lists.openstack.org
 home-page = https://docs.openstack.org/python-octaviaclient/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
@@ -107,15 +110,6 @@ openstack.load_balancer.v2 =
     loadbalancer_availabilityzone_set = octaviaclient.osc.v2.availabilityzone:SetAvailabilityzone
     loadbalancer_availabilityzone_unset = octaviaclient.osc.v2.availabilityzone:UnsetAvailabilityzone
 
-[build_sphinx]
-source-dir = doc/source
-build-dir = doc/build
-all_files = 1
-warning-is-error = 1
-
-[upload_sphinx]
-upload-dir = doc/build/html
-
 [compile_catalog]
 directory = octaviaclient/locale
 domain = octaviaclient
@@ -129,8 +123,3 @@ input_file = octaviaclient/locale/octaviaclient.pot
 keywords = _ gettext ngettext l_ lazy_gettext
 mapping_file = babel.cfg
 output_file = octaviaclient/locale/octaviaclient.pot
-
-[build_releasenotes]
-all_files = 1
-build-dir = releasenotes/build
-source-dir = releasenotes/source

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)