Fix up the xact_test for elog verification.
Fix up the xact_test for elog verification.

Originally, we didn't verify the correct error level in our helper method.

jmcatamney/gpdb,Chibin/gpdb,cjcjameson/gpdb,janebeckman/gpdb,Chibin/gpdb,lisakowen/gpdb,xinzweb/gpdb,janebeckman/gpdb,janebeckman/gpdb,jmcatamney/gpdb,xinzweb/gpdb,yuanzhao/gpdb,edespino/gpdb,janebeckman/gpdb,jmcatamney/gpdb,Quikling/gpdb,yuanzhao/gpdb,Quikling/gpdb,cjcjameson/gpdb,edespino/gpdb,janebeckman/gpdb,yuanzhao/gpdb,yuanzhao/gpdb,Quikling/gpdb,greenplum-db/gpdb,Quikling/gpdb,ashwinstar/gpdb,janebeckman/gpdb,adam8157/gpdb,lisakowen/gpdb,Quikling/gpdb,lisakowen/gpdb,greenplum-db/gpdb,50wu/gpdb,xinzweb/gpdb,edespino/gpdb,jmcatamney/gpdb,Quikling/gpdb,cjcjameson/gpdb,cjcjameson/gpdb,greenplum-db/gpdb,cjcjameson/gpdb,Chibin/gpdb,Chibin/gpdb,yuanzhao/gpdb,kaknikhil/gpdb,ashwinstar/gpdb,kaknikhil/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,kaknikhil/gpdb,adam8157/gpdb,Quikling/gpdb,ashwinstar/gpdb,greenplum-db/gpdb,edespino/gpdb,greenplum-db/gpdb,ashwinstar/gpdb,lisakowen/gpdb,Chibin/gpdb,Quikling/gpdb,cjcjameson/gpdb,50wu/gpdb,cjcjameson/gpdb,edespino/gpdb,janebeckman/gpdb,50wu/gpdb,Chibin/gpdb,yuanzhao/gpdb,cjcjameson/gpdb,adam8157/gpdb,edespino/gpdb,xinzweb/gpdb,lisakowen/gpdb,adam8157/gpdb,xinzweb/gpdb,kaknikhil/gpdb,janebeckman/gpdb,kaknikhil/gpdb,50wu/gpdb,cjcjameson/gpdb,xinzweb/gpdb,edespino/gpdb,janebeckman/gpdb,50wu/gpdb,yuanzhao/gpdb,kaknikhil/gpdb,edespino/gpdb,Quikling/gpdb,Quikling/gpdb,janebeckman/gpdb,greenplum-db/gpdb,50wu/gpdb,kaknikhil/gpdb,jmcatamney/gpdb,yuanzhao/gpdb,ashwinstar/gpdb,kaknikhil/gpdb,Chibin/gpdb,adam8157/gpdb,ashwinstar/gpdb,greenplum-db/gpdb,lisakowen/gpdb,jmcatamney/gpdb,50wu/gpdb,cjcjameson/gpdb,Chibin/gpdb,lisakowen/gpdb,ashwinstar/gpdb,ashwinstar/gpdb,yuanzhao/gpdb,kaknikhil/gpdb,Chibin/gpdb,yuanzhao/gpdb,xinzweb/gpdb,kaknikhil/gpdb,edespino/gpdb,50wu/gpdb,adam8157/gpdb,adam8157/gpdb,xinzweb/gpdb,edespino/gpdb,adam8157/gpdb,jmcatamney/gpdb,Chibin/gpdb,lisakowen/gpdb