Is the checkpoint rebuilder still meant to work from main()?

[Juhani Connolly]

Since the checkpoint rebuilding process uses up a fair bit more memory 
than normal operation of flume, I noted that there was a main() in 
CheckpointBuilder.java

For personal convenience I've made a patch to run this from the flume-ng 
script, and can of course share it(do we want this for the general release?)

One thing that came up though is that if I delete the contents of the 
checkpoint directory, the first run will error:

Exception in thread "main" java.io.IOException: File 
/tmp/flume-data/log-1.meta has bad version 1c0d0300
    at 
org.apache.flume.channel.file.LogFileFactory.getSequentialReader(LogFileFactory.java:169)
    at 
org.apache.flume.channel.file.CheckpointRebuilder.rebuild(CheckpointRebuilder.java:68)
    at 
org.apache.flume.channel.file.CheckpointRebuilder.main(CheckpointRebuilder.java:257)

The second time I run it, it will go through fine. Things appear to be 
running ok.

Should this still work or is the main() deprecated? Anyone more familiar 
have an idea as to what is causing the exception the first run through? 
Should I make an issue to share this?