psql: Improve expanded print output in tuples-only mode

When there are zero result rows, in expanded mode, "(No rows)" is
printed.  So far, there was no way to turn this off.  Now, when
tuples-only mode is turned on, nothing is printed in this case.
psql: Improve unaligned expanded output for zero rows

This used to erroneously print an empty line.  Now it prints nothing.
Add an example of attaching a default value to an updatable view.

This is probably the single most useful thing that ALTER VIEW can do,
particularly now that we have auto-updatable views.  So show an explicit
example.
Reduce log level of picksplit-doesn't-support-secondary-split whining.

This was agreed to back in 2007, but never actually done.

Josh Hansen