Add a further customization to the SGML Emacs mode to prevent the use of tabs in the documentation source.
Add a further customization to the SGML Emacs mode to prevent the use of
tabs in the documentation source.

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