By default, the database redo uses to store file state returns filenames
as Unicode strings, and if redo tries to run a build-script whose
fully-qualified path contains non-ASCII characters then redo crashes
when trying to promote the path to a Unicode string.
This patch ensures that the database always returns byte-strings, not
Unicode strings. That way, the fully-qualified path and the target name
are both byte-strings and can be joined without issue.
(Fixes a bug reported by Zoran Zaric.)
