default fsenc patch

[Martin Pool]

Hi,

Around the end of 2011 (which seems like a long time ago) there was
some discussion in the bzr and python bug trackers about how to handle
filename encoding when the locale is not set or is null.  I think this
ended up with bzr taking the patch to set the fsenc, but Python
rejecting it.

I wonder if we should actually follow the course of upstream Python
and just insist the user set eg LANG=C.UTF-8 if they have UTF-8 names,
and just focus on giving clear messages when names can't be decoded.

-- 
Martin