Do not try to stuff "HS_DESC_DECODE_GENERIC_ERROR" (-1) into a
socks5_reply_status_t (enum).  It doesn't actually make sense, and
isn't one of our documented extensions.

(This can only happen on a nonfatal assertion that we haven't seen,
so it probably isn't happening in practice.)

Fixes another case of bug 34077; bugfix on 0.4.3.1-alpha.