pep8: Return ability to run pylint only on given patches

This commit [1] removed ability to run pylint only on files
that were modified by latest patches. This patch adds it back.

[1] be77ed3a81

Change-Id: Ic6cbe9c9639b976a46fb2858c10c9caf0c998bbf
Signed-off-by: Jakub Libosvar <jlibosva@redhat.com>

TESTING.rst

@@ -449,7 +449,7 @@ to run.
 To restrict the pylint check to only the files altered by the latest patch
 changes::
 
-    tox -e pep8 HEAD~1
+    tox -e pep8 -- HEAD~1
 
 To run only the unit tests::
 

tools/coding-checks.sh

@@ -28,7 +28,10 @@ process_options () {
 run_pylint () {
     local target="${scriptargs:-all}"
 
+    echo "Running pylint..."
+
     if [ "$target" = "all" ]; then
+        echo "You can speed this up by running it on 'HEAD~[0-9]' (e.g. HEAD~1, this change only)..."
         files="neutron"
     else
         case "$target" in
@@ -36,9 +39,6 @@ run_pylint () {
             *) echo "$target is an unrecognized basecommit"; exit 1;;
         esac
     fi
-
-    echo "Running pylint..."
-    echo "You can speed this up by running it on 'HEAD~[0-9]' (e.g. HEAD~1, this change only)..."
     echo ""
     echo "Consider using the 'pre-commit' tool instead."
     echo ""

tox.ini

@@ -143,10 +143,12 @@ deps =
   pre-commit~=4.0 # MIT
 commands =
   pre-commit run --all-files --show-diff-on-failure
-  pylint --rcfile=.pylintrc --output-format=colorized neutron
+  bash ./tools/coding-checks.sh --pylint '{posargs}'
   neutron-db-manage --config-file neutron/tests/etc/neutron.conf check_migration
   {[testenv:genconfig]commands}
   {[testenv:genpolicy]commands}
+allowlist_externals =
+  bash
 
 [testenv:cover]
 description =