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.

include Makefile hgsubversion/help/*.rst tests/fixtures/invalid_utf8.tar.gz
recursive-include tests *.py *.sh *.svndump *.txt