Removed rmtree_errorhandler.

The stated reason for its introduction in d18d37ce no longer applies
since Django's code repository was switched from Subversion to git.

Furthermore it never had any effect because shutil.rmtree ignores its
onerror argument when ignore_errors is True.

The reason for its use in template management commands is unclear.

tests/staticfiles_tests/tests.py

@@ -20,7 +20,7 @@ from django.core.management import call_command
 from django.template import Context, Template
 from django.test import TestCase, override_settings
 from django.utils import six
-from django.utils._os import rmtree_errorhandler, symlinks_supported, upath
+from django.utils._os import symlinks_supported, upath
 from django.utils.encoding import force_text
 from django.utils.functional import empty
 
@@ -106,9 +106,7 @@ class BaseCollectionTestCase(BaseStaticFilesTestCase):
         self.patched_settings = self.settings(STATIC_ROOT=temp_dir)
         self.patched_settings.enable()
         self.run_collectstatic()
-        # Use our own error handler that can handle .svn dirs on Windows
-        self.addCleanup(shutil.rmtree, temp_dir,
-                        ignore_errors=True, onerror=rmtree_errorhandler)
+        self.addCleanup(shutil.rmtree, temp_dir)
 
     def tearDown(self):
         self.patched_settings.disable()