Hadoop 2.0 Upgrade

Following change set contains the changes required for hadoop 2.0 upgrade.

* All the tests which depended on Hadoop library have been modified to use Mockito.
* Pom file has been modified to generate two different artifacts based on profiles.
* Added two new build profiles
  * hadoop-1.0 -> builds distcp for Hadoop 1.0 and generates an artifact which has "-cdh3" appended to artifact name.
  * hadoop-2.0 -> builds distcp for Hadoop 2.0 and generates an artifcat which has "-cdh4" appended to artifact name.
* Removed legacy test from TestUniformInputFormat test case, as per HADOOP-9230
* Copied the *RetriableCommand* dependency from hadoop-1.0 and renamed the package to work around incompatibilities.
* Changed Test cases and removed MockJobTrackers dependency on JobSubmissionProtocol.