pgsql: Add warning about the need to increase "max_fsm_relations" and

Log Message:
-----------
Add warning about the need to increase "max_fsm_relations" and
"max_fsm_relations" for vacuums. Also improve VACUUM VERBOSE final
message text.

Ron Mayer

Modified Files:
--------------
pgsql/src/backend/storage/freespace:
freespace.c (r1.37 -> r1.38)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/storage/freespace/freespace.c.diff?r1=1.37&r2=1.38)