[VOTE] Freeze date for Common, HDFS, and MapReduce 0.21

[Owen O'Malley]

All,
   After the discussion settled last time, it seems that HDFS needs  
more time to settle append and sync. Therefore, I'd like to propose a  
freeze time of 4:30 pst on 18 Sep for making the 0.21 branch for  
Common, HDFS, and MapReduce.

-- Owen