Fix failing tests unde rpython-2.5.2 on a 64bit host.

* bzrlib/tests/workingtree_implementations/test_parents.py:
(TestSetParents.test_unicode_symlink): Fix another test failure by
also catching UnicodeWarning issued when selftest is run with a
ptyinh -Werror option.

* bzrlib/repository.py:
(CommitBuilder.record_entry_contents): Fix typo.


* bzrlib/dirstate.py:
(DirState._read_link): Don't encode abspath as it may fail under
unclear circumstances and isn't necessay to make the test suite
pass.