Cleanup py27 support

Make a few cleanups:
- 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: I89db151454b391bbc5f7f89d7886a8fbfb517d0d

setup.cfg

@@ -15,6 +15,7 @@ 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 :: 3.6
     Programming Language :: Python :: 3.7
@@ -36,20 +37,8 @@ oslo.config.opts =
 oslo.config.opts.defaults =
     rally = rally.common.opts:update_opt_defaults
 
-[global]
-setup-hooks =
-    pbr.hooks.setup_hook
-
 [extras]
 mysql =
   PyMySQL>=0.7.6  # MIT
 postgres =
   psycopg2>=2.5  # LGPL/ZPL
-
-[build_sphinx]
-all_files = 1
-build-dir = doc/build
-source-dir = doc/source
-
-[wheel]
-universal = 1

test-requirements.txt

@@ -4,7 +4,7 @@
 
 hacking>=3.0,<3.1.0 # Apache-2.0
 
-pytest>=2.7;python_version>'3.4'                       # MIT
+pytest>=2.7                                            # MIT
 # py.test plugin for measuring coverage.
 pytest-cov>=2.2.1                                      # MIT
 # py.test plugin for generating HTML reports