Problems with 0.16.1

[Owen O'Malley]

We believe that there has been a regression in release 0.16.1 with  
respect to the reliability of HDFS. In particular, tasks get stuck  
talking to the data nodes when they are under load. It seems to be  
HADOOP-3033. We are currently testing it further. In the mean time, I  
would suggest holding off 0.16.1.

-- Owen