fix "git fat pull" for fancy named files

[michaelcontento]

Hi,

in this PR I've just added -z to git ls-files and the result is split at \x00 instead of \n (as this is the new separator).

A simple change but now we're getting the original filename back from git and are able to handle names containing spaces and/or fancy utf8 characters.

Feel free to request changes if I missed something crucial.

[jedbrown]

Thanks, this looks good. There are a couple other places that either

• Pass unicode as a command-line argument, which we'd rather avoid because it forces us to encode (at least on Windows)
• We still use git ls-files -s in cmd_index_filter. It should also learn to use the -z option, but unfortunately, Python doesn't have convenient line processing for NUL-delimited streams so we have to write something like difftreez_reader to do that properly.

Anyway, these are topics for another time, so I'll merge this patch as is. (Nit: it's nice to use the same quote character as is used nearby unless there is a reason to use a different one.)