ZODB expect userid and description to be bytes

[gliheng]

ZODB expect user and description to be bytes.

as in ZODB/FileStorage/format.py

def asString(self):
        s = struct.pack(TRANS_HDR, self.tid, self.tlen, as_bytes(self.status),
                        self.ulen, self.dlen, self.elen)
        return b"".join(map(as_bytes, [s, self.user, self.descr, self.ext]))

Chinese username or pathinfo will throw an exception here.

[tseaver]

Thank you for the patch! Unfortunately, the transaction actually needs the description and user to be native strings, so your fix won't work on Python3. I'm working on a fix based on #25.