conversion problem

When trying to insert strings with German umlaute (e.g. "täglich") into
a text or varchar column, the server throws the message
invalid byte sequence for encoding "UNICODE": 0xe4656c

This results from ResolveOneParam not converting the string to UTF-8.
From debugging I found that ipdopts->parameters[param_number].SQLType
contains 0xffff, instead of something sensible for PGType=0x19 (text).

The attached patch works as hotfix for me, but is certainly only a
workaround for a problem buried deeper because SQLType seems bogus to me.

OTOH, I don't understand why the switch(param_pgtype) was invented at
all (the original patch I posted more than a year ago didn't have it),
because any string coming from the app will probably need conversion to
UTF-8 anyway.

Regards,
Andreas