Remove docs missed in 51c11a7025.
Remove docs missed in 51c11a7025.

Somehow I misresolved a merge conflict when forward porting Petr's patch
leading to a section of the docs remaining...

Thankfully Fujii spotted my mistake.

Postgres-XL/Postgres-XL,xinzweb/gpdb,jmcatamney/gpdb,Postgres-XL/Postgres-XL,oberstet/postgres-xl,oberstet/postgres-xl,zeroae/postgres-xl,adam8157/gpdb,lisakowen/gpdb,ovr/postgres-xl,greenplum-db/gpdb,lisakowen/gpdb,50wu/gpdb,pavanvd/postgres-xl,jmcatamney/gpdb,lisakowen/gpdb,xinzweb/gpdb,jmcatamney/gpdb,zeroae/postgres-xl,50wu/gpdb,adam8157/gpdb,adam8157/gpdb,jmcatamney/gpdb,adam8157/gpdb,zeroae/postgres-xl,pavanvd/postgres-xl,lisakowen/gpdb,oberstet/postgres-xl,zeroae/postgres-xl,pavanvd/postgres-xl,xinzweb/gpdb,zeroae/postgres-xl,jmcatamney/gpdb,yazun/postgres-xl,Postgres-XL/Postgres-XL,greenplum-db/gpdb,lisakowen/gpdb,ashwinstar/gpdb,oberstet/postgres-xl,xinzweb/gpdb,greenplum-db/gpdb,pavanvd/postgres-xl,adam8157/gpdb,greenplum-db/gpdb,50wu/gpdb,jmcatamney/gpdb,lisakowen/gpdb,lisakowen/gpdb,greenplum-db/gpdb,50wu/gpdb,yazun/postgres-xl,greenplum-db/gpdb,ashwinstar/gpdb,adam8157/gpdb,techdragon/Postgres-XL,ashwinstar/gpdb,xinzweb/gpdb,techdragon/Postgres-XL,lisakowen/gpdb,ashwinstar/gpdb,Postgres-XL/Postgres-XL,ashwinstar/gpdb,50wu/gpdb,ovr/postgres-xl,yazun/postgres-xl,yazun/postgres-xl,pavanvd/postgres-xl,ovr/postgres-xl,ashwinstar/gpdb,ashwinstar/gpdb,50wu/gpdb,greenplum-db/gpdb,ashwinstar/gpdb,yazun/postgres-xl,oberstet/postgres-xl,adam8157/gpdb,techdragon/Postgres-XL,ovr/postgres-xl,xinzweb/gpdb,jmcatamney/gpdb,jmcatamney/gpdb,techdragon/Postgres-XL,xinzweb/gpdb,adam8157/gpdb,50wu/gpdb,greenplum-db/gpdb,ovr/postgres-xl,Postgres-XL/Postgres-XL,50wu/gpdb,techdragon/Postgres-XL,xinzweb/gpdb