Doc: update URL for check_postgres.
Doc: update URL for check_postgres.

Reported by Dan Vianello.

Discussion: 3c5afab925b2341617ab906826b05fbcd105969e@KSTLMEXGP001.CORP.CHARTERCOM.com

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