Fix obsolete comment regarding NOTICE message level.
Fix obsolete comment regarding NOTICE message level.

By default NOTICE message is not sent to server log because
the default value of log_min_messages is WARNING since 8.4.

Pavel Stehule

50wu/gpdb,xinzweb/gpdb,jmcatamney/gpdb,lisakowen/gpdb,xinzweb/gpdb,jmcatamney/gpdb,ashwinstar/gpdb,greenplum-db/gpdb,50wu/gpdb,adam8157/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,50wu/gpdb,adam8157/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,adam8157/gpdb,ashwinstar/gpdb,greenplum-db/gpdb,adam8157/gpdb,50wu/gpdb,xinzweb/gpdb,ashwinstar/gpdb,50wu/gpdb,jmcatamney/gpdb,xinzweb/gpdb,xinzweb/gpdb,ashwinstar/gpdb,lisakowen/gpdb,adam8157/gpdb,ashwinstar/gpdb,xinzweb/gpdb,lisakowen/gpdb,xinzweb/gpdb,greenplum-db/gpdb,lisakowen/gpdb,greenplum-db/gpdb,lisakowen/gpdb,adam8157/gpdb,50wu/gpdb,50wu/gpdb,adam8157/gpdb,jmcatamney/gpdb,ashwinstar/gpdb,50wu/gpdb,lisakowen/gpdb,lisakowen/gpdb,lisakowen/gpdb,ashwinstar/gpdb,adam8157/gpdb,jmcatamney/gpdb,ashwinstar/gpdb,greenplum-db/gpdb,xinzweb/gpdb