[MERGE][1.12][URGENT] Fix failing tests under rpython-2.5.2 on a 64bit host.

[Jelmer Vernooij]

Jelmer Vernooij has voted resubmit.
Status is now: Resubmit
Comment:
This may fix the build with C extensions built, it breaks them without C 
extensions. py_update_entry() calls _read_link() with a unicode object 
argument, while the C extensions call it with a utf8 string.

For details, see: 
http://bundlebuggy.aaronbentley.com/project/bzr/request/%3Cm2iqneo63n.fsf%40free.fr%3E
Project: Bazaar