Keep heap_page_prune from marking the buffer dirty when it didn't really change anything.  Per report from Itagaki Takahiro.  Fix by Pavan Deolasee.
Keep heap_page_prune from marking the buffer dirty when it didn't
really change anything.  Per report from Itagaki Takahiro.  Fix by
Pavan Deolasee.

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