I think this should go away:
ereport(NOTICE,
(errmsg("created replication slot \"%s\" on
publisher",
slotname)));
It doesn't appear to be contingent on anything other than the content of
the command you just gave it. I don't think we need a NOTICE saying that
it did that thing I just told it to do--that should be implicit by the lack
of an ERROR.
Cheers,
Jeff