File descriptor leak in tdlookup.c:respond

Has anyone noticed there's a potential file descriptor leak in
tdlookup.c's respond() function?  I searched for this issue for a
little bit, and I couldn't find anything about it.

If there's a cdb_read error while looking up the client's location,
then the data.cdb file descriptor is never closed.  (cdb_free(&c) is
also not called, but cdb_init(&c,fd) first calls cdb_free(&c), so it
doesn't leak memory.)  In practice, I don't think this is a problem
because I think the only reason cdb_read might realistically error is
because of a misformatted cdb file, which tinydns-data won't build.