Saner error handling in typed_wu()

Saner error handling in typed_wu()

Leave nat_ann, nat_tgm alone and return -1 on all errors.  Before,
only failed open was handled that way.  Failed write and close were
logged and ignored.  While there, improve the log messages a bit.

Note: the return value fix has little effect.  It makes tele() log the
failure, which is redundant.  Everything else goes through wu() and
ignores the value.