Re-enable pg_upgrade, after adding checks that the source and target databases are of versions it knows about.
Re-enable pg_upgrade, after adding checks that the source
and target databases are of versions it knows about.

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