Include nodetag in squelching error
Include nodetag in squelching error

This mimicks the error messaging in ExecSquelchNode() for when the
node type is unknown, to aid debugging.

Also removes a header comment which was made obsolete in commit
6195b96780.

Reviewed-by: Heikki Linnakangas <9304c20251d03f4d84fc732cc8196e9ef6638e64@pivotal.io>

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