Drop no-longer-needed custom changes to /usr/bin/pip*

pip >= 20 has a mechanism that replaces our pip-allow-different-versions.patch
However, we kept our patch to support users doing e.g.:

    $ pip install --user --upgrade 'pip<20'

However, pip 19.3.1 (the latest <20 version) does not even operate without distutils:

    (venv3.12)$ pip list
    Package    Version
    ---------- -------
    pip        22.3.1
    setuptools 65.5.0

    (venv3.12)$ pip install --upgrade 'pip<20'
    ...

    (venv3.12) $ pip list
    Traceback (most recent call last):
      File ".../venv3.12/bin/pip", line 5, in <module>
        from pip._internal.main import main
      File ".../venv3.12/lib64/python3.12/site-packages/pip/_internal/main.py", line 13, in <module>
        from pip._internal.cli.autocompletion import autocomplete
      File ".../venv3.12/lib64/python3.12/site-packages/pip/_internal/cli/autocompletion.py", line 11, in <module>
        from pip._internal.cli.main_parser import create_main_parser
      File ".../venv3.12/lib64/python3.12/site-packages/pip/_internal/cli/main_parser.py", line 7, in <module>
        from pip._internal.cli import cmdoptions
      File ".../venv3.12/lib64/python3.12/site-packages/pip/_internal/cli/cmdoptions.py", line 19, in <module>
        from distutils.util import strtobool
    ModuleNotFoundError: No module named 'distutils'

Hence, it no longer makes any sense to keep the patch with Python 3.12.

pip-allow-different-versions.patch

@@ -1,27 +0,0 @@
---- /usr/bin/pip3	2019-11-12 17:37:34.793131862 +0100
-+++ pip3	2019-11-12 17:40:42.014107134 +0100
-@@ -2,7 +2,23 @@
- # -*- coding: utf-8 -*-
- import re
- import sys
--from pip._internal.cli.main import main
-+
-+try:
-+    from pip._internal.cli.main import main
-+except ImportError:
-+    try:
-+        from pip._internal.main import main
-+    except ImportError:
-+        try:
-+            # If the user has downgraded pip, the above import will fail.
-+            # Let's try older methods of invoking it:
-+
-+            # pip 19 uses this
-+            from pip._internal import main
-+        except ImportError:
-+            # older pip versions use this
-+            from pip import main
-+
- if __name__ == '__main__':
-     sys.argv[0] = re.sub(r'(-script\.pyw|\.exe)?$', '', sys.argv[0])
-     sys.exit(main())

python-pip.spec

@@ -16,7 +16,7 @@
 
 Name:           python-%{srcname}
 Version:        %{base_version}%{?prerel:~%{prerel}}
-Release:        5%{?dist}
+Release:        6%{?dist}
 Summary:        A tool for installing and managing Python packages
 
 # We bundle a lot of libraries with pip, which itself is under MIT license.
@@ -85,29 +85,6 @@ Patch:          nowarn-pip._internal.main.patch
 # Upstream issue: https://github.com/pypa/packaging/issues/368
 Patch:          no-version-warning.patch
 
-# Downstream only patch
-# Users might have local installations of pip from using
-# `pip install --user --upgrade pip` on older/newer versions.
-# If they do that and they run `pip` or  `pip3`, the one from /usr/bin is used.
-# However that's the one from this RPM package and the import in there might
-# fail (it tries to import from ~/.local, but older or newer pip is there with
-# a bit different API).
-# We add this patch as a dirty workaround to make /usr/bin/pip* work with
-# both pip10+ (from this RPM) and older or newer (19.3+) pip (from whatever).
-# A proper fix is to put ~/.local/bin in front of /usr/bin in the PATH,
-# however others are against that and we cannot change it for existing
-# installs/user homes anyway.
-# https://bugzilla.redhat.com/show_bug.cgi?id=1569488
-# https://bugzilla.redhat.com/show_bug.cgi?id=1571650
-# https://bugzilla.redhat.com/show_bug.cgi?id=1767212
-# WARNING: /usr/bin/pip* are entrypoints, this cannot be applied in %%prep!
-# %%patch10 doesn't work outside of %%prep, so we add it as a source
-# Note that since pip 20, old main() import paths are preserved for backwards
-# compatibility: https://github.com/pypa/pip/issues/7498
-# Meaning we don't need to update any of the older pips to support 20+
-# We also don't need to update Pythons to use new import path in ensurepip
-Source10:        pip-allow-different-versions.patch
-
 %description
 pip is a package management system used to install and manage software packages
 written in Python. Many packages can be found in the Python Package Index
@@ -309,11 +286,6 @@ done
 popd
 %endif
 
-# before we ln -s anything, we apply Source10 patch to all pips:
-for PIP in %{buildroot}%{_bindir}/pip*; do
-  patch -p1 --no-backup-if-mismatch $PIP < %{SOURCE10}
-done
-
 mkdir -p %{buildroot}%{bashcompdir}
 PYTHONPATH=%{buildroot}%{python3_sitelib} \
     %{buildroot}%{_bindir}/pip completion --bash \
@@ -389,6 +361,10 @@ pytest_k='not completion'
 %{python_wheel_dir}/%{python_wheel_name}
 
 %changelog
+* Wed Jul 26 2023 Miro Hrončok <mhroncok@redhat.com> - 23.1.2-6
+- Drop no-longer-needed custom changes to /usr/bin/pip*
+Resolves: rhbz#2150373
+
 * Tue Jul 25 2023 Python Maint <python-maint@redhat.com> - 23.1.2-5
 - Rebuilt for Python 3.12