Remove unused variable
Remove unused variable

While PyGreSQL is a vendored module, the pg_notices() function is
a local patch added a very long time ago. The variable removed by
this has been unused for that same very long time, so it's about
time.

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