Remove one copy of duplicated alpha4 release note.
Remove one copy of duplicated alpha4 release note.

Noted by Andy Colson

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