clone: add try/finally to unwrap While fixing other test failures, I saw stack overflows related to the clone function being wrapped too many times. I believe it's because this wrapping logic doesn't put the unwrap logic in a finally statement. This particularly bad in the tests, which do many things in one process. Hence the stack overflow.

import test_util

import unittest

class TestFetchBinaryFiles(test_util.TestBase):
    stupid_mode_tests = True

    def test_binaryfiles(self):
        repo = self._load_fixture_and_fetch('binaryfiles.svndump')
        self.assertEqual('cce7fe400d8d', str(repo['tip']))