Fixed a F811 warning introduced by 35db9d58.

        """The storage backend should preserve case of filenames."""

        # Create a storage backend associated with the mixed case name

        # directory.

        temp_storage = self.storage_class(location=self.temp_dir2)

        other_temp_storage = self.storage_class(location=self.temp_dir2)

        # Ask that storage backend to store a file with a mixed case filename.

        mixed_case = 'CaSe_SeNsItIvE'

        file = temp_storage.open(mixed_case, 'w')

        file = other_temp_storage.open(mixed_case, 'w')

        file.write('storage contents')

        file.close()

        self.assertEqual(os.path.join(self.temp_dir2, mixed_case),

                         temp_storage.path(mixed_case))

        temp_storage.delete(mixed_case)

                         other_temp_storage.path(mixed_case))

        other_temp_storage.delete(mixed_case)

    def test_makedirs_race_handling(self):

        """