Return Etag and Last-Modified values defaults to now for both.

def _conditions(self, full_path, environ):
        """Return Etag and Last-Modified values defaults to now for both."""
        magic = self._match_magic(full_path)
        if magic is not None:
            return magic.conditions(full_path, environ)
        else:
            mtime = stat(full_path).st_mtime
            return str(mtime), rfc822.formatdate(mtime)