Python code modernization, 8/n (#1179)

* Use to_text instead of to_native.

* Remove no longer needed pylint ignores.

* Remove another pylint ignore.

* Remove no longer needed ignore.

* Address redefined-outer-name.

* Address consider-using-with.

.pylintrc

@@ -379,18 +379,12 @@ disable=raw-checker-failed,
         wrong-import-order,
         wrong-import-position,
         # To clean up:
-        arguments-differ,
-        consider-using-with,
         fixme,
         import-error,  # TODO figure out why pylint cannot find the module
-        no-member,
         no-name-in-module,  # TODO figure out why pylint cannot find the module
-        not-an-iterable,  # TODO: needs better typing info
         protected-access,
-        redefined-outer-name,  # needed for test fixtures
         subprocess-popen-preexec-fn,
         unexpected-keyword-arg,
-        unsupported-assignment-operation,  # TODO: needs better typing info
         unused-argument,
         # Cannot remove yet due to inadequacy of rules
         inconsistent-return-statements,  # doesn't notice that fail_json() does not return