* Don't unstash the piper binary if it is already present.
* Fixed method name.
* Removed changes to unit test.
* Updated unit tests to account for the check whether the piper binary exists.
* Updated the Maven test to account for the piper binary existance check.
* Updated tests to account for the piper binary existance check.
* Set the shell return value for a test.
* See if it will output the real failure reason.
* Removed code that triggered a different error message if sh(Map) is encountered.
* Added missing constructor parameter.
* Pass the script to the constructor of PiperGoUtils.
* Reverted change to code that is now removed from the master branch.
* Re-instated deleted function.
* Re-add fix to use the correct constructor for PiperGoUtils.
