pgsql: Fix utterly-bogus code for computing row heights.

Log Message:
-----------
Fix utterly-bogus code for computing row heights.  Per crashes on
spoonbill, though one wonders why it didn't misbehave everywhere.
In passing remove some unnecessary modulo calculations.

Modified Files:
--------------
    pgsql/src/bin/psql:
        print.c (r1.103 -> r1.104)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/print.c?r1=1.103&r2=1.104)