This change removes the ShimLoader and various Shim classes such as CDH3Shim
etc. It introduces a couple of new classes - ConfigurationConstants and
ConfigurationHelper - that provide a unique place for articulating interface
related details such as configuration keys that can likely change from version
to version of Hadoop.
From: Arvind Prabhakar <arvind@cloudera.com>
git-svn-id: https://svn.apache.org/repos/asf/incubator/sqoop/trunk@1149994 13f79535-47bb-0310-9956-ffa450edef68
