[VOTE] Back-port TFile to Hadoop 0.20

[Hong Tang]

I have talked with a few folks in the community who are interested in  
using TFile (HADOOP-3315) in their projects that are currently  
dependent on Hadoop 0.20, and it would significantly simplify the  
release process as well as their lives if we could back port TFile to  
Hadoop 0.20 (instead of putting it on yhadoop 0.20).

To be clear, TFile is a new feature, but it only adds a new file  
format - no existing files are changed other than build.xml.

-Hong