Fix another place broken by new List implementation :-(.  Per example from goranpop@nspoint.net.  I think this escaped notice because in simple cases the list is NIL on entry.
Fix another place broken by new List implementation :-(.  Per example
from goranpop@nspoint.net.  I think this escaped notice because in
simple cases the list is NIL on entry.

kmjungersen/PostgresXL,randomtask1155/gpdb,jmcatamney/gpdb,postmind-net/postgres-xl,lpetrov-pivotal/gpdb,cjcjameson/gpdb,lintzc/gpdb,lisakowen/gpdb,CraigHarris/gpdb,Quikling/gpdb,ahachete/gpdb,rvs/gpdb,yuanzhao/gpdb,0x0FFF/gpdb,postmind-net/postgres-xl,randomtask1155/gpdb,yazun/postgres-xl,Chibin/gpdb,cjcjameson/gpdb,lintzc/gpdb,Chibin/gpdb,tpostgres-projects/tPostgres,chrishajas/gpdb,ahachete/gpdb,greenplum-db/gpdb,yuanzhao/gpdb,tpostgres-projects/tPostgres,kaknikhil/gpdb,rubikloud/gpdb,ashwinstar/gpdb,50wu/gpdb,chrishajas/gpdb,Postgres-XL/Postgres-XL,ovr/postgres-xl,oberstet/postgres-xl,jmcatamney/gpdb,CraigHarris/gpdb,chrishajas/gpdb,edespino/gpdb,royc1/gpdb,Quikling/gpdb,janebeckman/gpdb,zaksoup/gpdb,kmjungersen/PostgresXL,Quikling/gpdb,zaksoup/gpdb,royc1/gpdb,50wu/gpdb,xuegang/gpdb,randomtask1155/gpdb,janebeckman/gpdb,xuegang/gpdb,kaknikhil/gpdb,janebeckman/gpdb,adam8157/gpdb,edespino/gpdb,rubikloud/gpdb,yuanzhao/gpdb,foyzur/gpdb,yuanzhao/gpdb,chrishajas/gpdb,zaksoup/gpdb,0x0FFF/gpdb,Chibin/gpdb,jmcatamney/gpdb,xuegang/gpdb,0x0FFF/gpdb,foyzur/gpdb,Quikling/gpdb,Quikling/gpdb,Quikling/gpdb,zaksoup/gpdb,lpetrov-pivotal/gpdb,rvs/gpdb,tangp3/gpdb,rubikloud/gpdb,cjcjameson/gpdb,arcivanov/postgres-xl,lisakowen/gpdb,lpetrov-pivotal/gpdb,jmcatamney/gpdb,Postgres-XL/Postgres-XL,jmcatamney/gpdb,rubikloud/gpdb,tangp3/gpdb,janebeckman/gpdb,postmind-net/postgres-xl,Postgres-XL/Postgres-XL,atris/gpdb,foyzur/gpdb,atris/gpdb,tangp3/gpdb,zeroae/postgres-xl,snaga/postgres-xl,tangp3/gpdb,jmcatamney/gpdb,cjcjameson/gpdb,pavanvd/postgres-xl,CraigHarris/gpdb,ovr/postgres-xl,lisakowen/gpdb,greenplum-db/gpdb,lisakowen/gpdb,Chibin/gpdb,atris/gpdb,greenplum-db/gpdb,lisakowen/gpdb,snaga/postgres-xl,ashwinstar/gpdb,kmjungersen/PostgresXL,tpostgres-projects/tPostgres,Quikling/gpdb,snaga/postgres-xl,kaknikhil/gpdb,Chibin/gpdb,0x0FFF/gpdb,lpetrov-pivotal/gpdb,0x0FFF/gpdb,yazun/postgres-xl,lisakowen/gpdb,ashwinstar/gpdb,atris/gpdb,CraigHarris/gpdb,edespino/gpdb,kmjungersen/PostgresXL,ovr/postgres-xl,techdragon/Postgres-XL,zeroae/postgres-xl,50wu/gpdb,chrishajas/gpdb,xuegang/gpdb,ahachete/gpdb,50wu/gpdb,ashwinstar/gpdb,yuanzhao/gpdb,randomtask1155/gpdb,yuanzhao/gpdb,adam8157/gpdb,janebeckman/gpdb,Postgres-XL/Postgres-XL,xinzweb/gpdb,janebeckman/gpdb,kaknikhil/gpdb,xuegang/gpdb,lintzc/gpdb,CraigHarris/gpdb,foyzur/gpdb,oberstet/postgres-xl,edespino/gpdb,cjcjameson/gpdb,snaga/postgres-xl,CraigHarris/gpdb,Chibin/gpdb,rvs/gpdb,edespino/gpdb,Postgres-XL/Postgres-XL,tpostgres-projects/tPostgres,cjcjameson/gpdb,snaga/postgres-xl,foyzur/gpdb,janebeckman/gpdb,ahachete/gpdb,pavanvd/postgres-xl,rubikloud/gpdb,rvs/gpdb,randomtask1155/gpdb,ashwinstar/gpdb,yuanzhao/gpdb,cjcjameson/gpdb,tpostgres-projects/tPostgres,0x0FFF/gpdb,pavanvd/postgres-xl,zaksoup/gpdb,lintzc/gpdb,kaknikhil/gpdb,0x0FFF/gpdb,atris/gpdb,ahachete/gpdb,cjcjameson/gpdb,randomtask1155/gpdb,royc1/gpdb,greenplum-db/gpdb,postmind-net/postgres-xl,ovr/postgres-xl,arcivanov/postgres-xl,yuanzhao/gpdb,lintzc/gpdb,royc1/gpdb,techdragon/Postgres-XL,lpetrov-pivotal/gpdb,jmcatamney/gpdb,oberstet/postgres-xl,lintzc/gpdb,royc1/gpdb,tangp3/gpdb,kaknikhil/gpdb,adam8157/gpdb,xuegang/gpdb,arcivanov/postgres-xl,zaksoup/gpdb,yuanzhao/gpdb,lisakowen/gpdb,chrishajas/gpdb,oberstet/postgres-xl,zeroae/postgres-xl,janebeckman/gpdb,CraigHarris/gpdb,edespino/gpdb,rvs/gpdb,kmjungersen/PostgresXL,ashwinstar/gpdb,foyzur/gpdb,lpetrov-pivotal/gpdb,adam8157/gpdb,50wu/gpdb,ashwinstar/gpdb,Quikling/gpdb,xinzweb/gpdb,Quikling/gpdb,chrishajas/gpdb,zaksoup/gpdb,xinzweb/gpdb,oberstet/postgres-xl,lintzc/gpdb,adam8157/gpdb,xinzweb/gpdb,adam8157/gpdb,randomtask1155/gpdb,yuanzhao/gpdb,kaknikhil/gpdb,Chibin/gpdb,lpetrov-pivotal/gpdb,ahachete/gpdb,xuegang/gpdb,tangp3/gpdb,rvs/gpdb,greenplum-db/gpdb,ovr/postgres-xl,rvs/gpdb,CraigHarris/gpdb,royc1/gpdb,greenplum-db/gpdb,zeroae/postgres-xl,xuegang/gpdb,edespino/gpdb,rubikloud/gpdb,janebeckman/gpdb,edespino/gpdb,Chibin/gpdb,Quikling/gpdb,Chibin/gpdb,adam8157/gpdb,rvs/gpdb,postmind-net/postgres-xl,xinzweb/gpdb,xinzweb/gpdb,Chibin/gpdb,0x0FFF/gpdb,rubikloud/gpdb,xuegang/gpdb,techdragon/Postgres-XL,ashwinstar/gpdb,zeroae/postgres-xl,techdragon/Postgres-XL,lpetrov-pivotal/gpdb,ahachete/gpdb,zaksoup/gpdb,yazun/postgres-xl,xinzweb/gpdb,50wu/gpdb,lintzc/gpdb,cjcjameson/gpdb,pavanvd/postgres-xl,rubikloud/gpdb,tangp3/gpdb,pavanvd/postgres-xl,greenplum-db/gpdb,atris/gpdb,atris/gpdb,arcivanov/postgres-xl,techdragon/Postgres-XL,lintzc/gpdb,edespino/gpdb,edespino/gpdb,adam8157/gpdb,arcivanov/postgres-xl,50wu/gpdb,janebeckman/gpdb,kaknikhil/gpdb,jmcatamney/gpdb,xinzweb/gpdb,50wu/gpdb,arcivanov/postgres-xl,randomtask1155/gpdb,yazun/postgres-xl,yazun/postgres-xl,lisakowen/gpdb,ahachete/gpdb,rvs/gpdb,tangp3/gpdb,CraigHarris/gpdb,kaknikhil/gpdb,royc1/gpdb,rvs/gpdb,foyzur/gpdb,greenplum-db/gpdb,cjcjameson/gpdb,chrishajas/gpdb,royc1/gpdb,atris/gpdb,kaknikhil/gpdb,foyzur/gpdb