Log Message:
-----------
Change the delta val from 0 and 10000 to -5000 and 5000 per recent
discussion in hackers list. Also enhance predefined benchmark
scenarios to reflect the scaling factor parameter flexibly.
Modified Files:
--------------
pgsql/contrib/pgbench:
pgbench.c (r1.50 -> r1.51)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/pgbench/pgbench.c.diff?r1=1.50&r2=1.51)