Now that YARN has been put in to trunk we should do something similar to
MAPREDUCE-849. We should go back and look at all of the configurations that have been added in and rename them as needed to be consistent and subdivided by component.
- We should use all lowercase in the config names. e.g., we should use appsmanager instead of appsManager etc.
- history server config names should be prefixed with mapreduce instead of yarn.