Improve postgresql.conf descriptions.
Improve postgresql.conf descriptions.

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