Produce a more specific error message when backend sees EOF on client connection.
Produce a more specific error message when backend sees EOF on
client connection.

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