Create a script to automate the fsimage export

[ryanhennig-ebaysf]

I'm working on automation for the steps required to export the fsimage and process it for input into hdfs-du. I'm currently doing this as a shell script designed to run from the secondary name node.

I'm already wishing this was in a language like ruby or python. I'm more familiar with ruby so that is my first inclination, but the project already has a dependency on python, so that might make sense as well.

[cbaenziger]

Though frozen now, it may help folks to see we at Bloomberg did write an Oozie workflow and Chef recipes to deploy HDFS-DU in https://github.com/bloomberg/chef-bach/pull/932