Fix bug with page deletion. If inner page is removed and it tries to remove page on next level linked from next inner page, ginScanToDelete() wrongly sets parent page. Bug reveals when many item pointers from index was deleted ( several hundred thousands).
Fix bug with page deletion. If inner page is removed and it tries to
remove page on next level linked from next inner page, ginScanToDelete()
wrongly sets parent page. Bug reveals when many item pointers from index
was deleted ( several hundred thousands).

Bug is discovered by hubert depesz lubaczewski <depesz@gmail.com>

Suppose, we need rc2 before release...

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