Remove some notes no longer valid

setup.py is no longer maintained by the global sync. Also the note
in requirements.txt does not apply since pip 20.3. This also removes
workaround for old python which we no longer support.

[1] https://lists.openstack.org/pipermail/openstack-discuss/2023-June/034073.html

Change-Id: If0ea61f0b13f2a76720f30236aae57045cfc48a6
diff --git a/requirements.txt b/requirements.txt
index 43abf78..ed5a98c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,3 @@
-# The order of packages is significant, because pip processes them in the order
-# of appearance. Changing the order has an impact on the overall integration
-# process, which may cause wedges in the gate later.
 keystoneauth1>=3.4.0 # Apache-2.0
 oslo.config>=5.2.0 # Apache-2.0
 oslo.log>=3.36.0 # Apache-2.0
diff --git a/setup.py b/setup.py
index 566d844..cd35c3c 100644
--- a/setup.py
+++ b/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)