Remove support of backward scan in GiST. Per discussion http://archives.postgresql.org/pgsql-hackers/2008-10/msg00857.php
Remove support of backward scan in GiST. Per discussion
http://archives.postgresql.org/pgsql-hackers/2008-10/msg00857.php

edespino/gpdb,Chibin/gpdb,greenplum-db/gpdb,postmind-net/postgres-xl,kmjungersen/PostgresXL,50wu/gpdb,greenplum-db/gpdb,arcivanov/postgres-xl,xinzweb/gpdb,oberstet/postgres-xl,kmjungersen/PostgresXL,techdragon/Postgres-XL,yazun/postgres-xl,oberstet/postgres-xl,adam8157/gpdb,edespino/gpdb,techdragon/Postgres-XL,adam8157/gpdb,yazun/postgres-xl,snaga/postgres-xl,arcivanov/postgres-xl,50wu/gpdb,xinzweb/gpdb,yazun/postgres-xl,ovr/postgres-xl,ashwinstar/gpdb,xinzweb/gpdb,zeroae/postgres-xl,edespino/gpdb,Chibin/gpdb,greenplum-db/gpdb,postmind-net/postgres-xl,tpostgres-projects/tPostgres,ashwinstar/gpdb,adam8157/gpdb,50wu/gpdb,arcivanov/postgres-xl,edespino/gpdb,greenplum-db/gpdb,greenplum-db/gpdb,yazun/postgres-xl,techdragon/Postgres-XL,snaga/postgres-xl,pavanvd/postgres-xl,Chibin/gpdb,adam8157/gpdb,xinzweb/gpdb,snaga/postgres-xl,tpostgres-projects/tPostgres,oberstet/postgres-xl,postmind-net/postgres-xl,snaga/postgres-xl,yuanzhao/gpdb,tpostgres-projects/tPostgres,Chibin/gpdb,lisakowen/gpdb,kmjungersen/PostgresXL,greenplum-db/gpdb,greenplum-db/gpdb,lisakowen/gpdb,50wu/gpdb,50wu/gpdb,arcivanov/postgres-xl,kmjungersen/PostgresXL,postmind-net/postgres-xl,ashwinstar/gpdb,adam8157/gpdb,Postgres-XL/Postgres-XL,edespino/gpdb,jmcatamney/gpdb,Chibin/gpdb,tpostgres-projects/tPostgres,50wu/gpdb,Chibin/gpdb,jmcatamney/gpdb,edespino/gpdb,tpostgres-projects/tPostgres,adam8157/gpdb,edespino/gpdb,greenplum-db/gpdb,yuanzhao/gpdb,yuanzhao/gpdb,Postgres-XL/Postgres-XL,Postgres-XL/Postgres-XL,xinzweb/gpdb,arcivanov/postgres-xl,jmcatamney/gpdb,yuanzhao/gpdb,adam8157/gpdb,50wu/gpdb,xinzweb/gpdb,ashwinstar/gpdb,50wu/gpdb,lisakowen/gpdb,lisakowen/gpdb,pavanvd/postgres-xl,edespino/gpdb,pavanvd/postgres-xl,ashwinstar/gpdb,ovr/postgres-xl,yazun/postgres-xl,jmcatamney/gpdb,xinzweb/gpdb,snaga/postgres-xl,jmcatamney/gpdb,techdragon/Postgres-XL,ovr/postgres-xl,oberstet/postgres-xl,jmcatamney/gpdb,yuanzhao/gpdb,ashwinstar/gpdb,yuanzhao/gpdb,yuanzhao/gpdb,lisakowen/gpdb,ovr/postgres-xl,pavanvd/postgres-xl,Postgres-XL/Postgres-XL,kmjungersen/PostgresXL,postmind-net/postgres-xl,Chibin/gpdb,yuanzhao/gpdb,jmcatamney/gpdb,zeroae/postgres-xl,Chibin/gpdb,edespino/gpdb,zeroae/postgres-xl,techdragon/Postgres-XL,xinzweb/gpdb,ashwinstar/gpdb,zeroae/postgres-xl,Postgres-XL/Postgres-XL,zeroae/postgres-xl,yuanzhao/gpdb,edespino/gpdb,Chibin/gpdb,Chibin/gpdb,ovr/postgres-xl,lisakowen/gpdb,arcivanov/postgres-xl,ashwinstar/gpdb,oberstet/postgres-xl,lisakowen/gpdb,pavanvd/postgres-xl,yuanzhao/gpdb,jmcatamney/gpdb,adam8157/gpdb,lisakowen/gpdb