Disable log subsystem (#6628)

toolset/databases/postgres/postgresql.conf

@@ -294,7 +294,7 @@ max_wal_senders = 0		# max number of walsender processes
 
 # - Where to Log -
 
-#log_destination = 'stderr'		# Valid values are combinations of
+log_destination = ''		# Valid values are combinations of
 					# stderr, csvlog, syslog, and eventlog,
 					# depending on platform.  csvlog
 					# requires logging_collector to be on.