Jenkinsfile: Clean the code
Jenkinsfile: Clean the code

Clean the code by reducing the amount of 'if' clauses and simplify the
logic.

Signed-off-by: Simo Kuusela <4755938158c3c622d3884e9a75ed20dc865bc695@intel.com>

mythi/intel-iot-refkit,mythi/intel-iot-refkit,klihub/intel-iot-refkit,jairglez/intel-iot-refkit,intel/intel-iot-refkit,intel/intel-iot-refkit,jairglez/intel-iot-refkit,klihub/intel-iot-refkit,ipuustin/intel-iot-refkit,intel/intel-iot-refkit,YinThong/intel-iot-refkit,mythi/intel-iot-refkit,klihub/intel-iot-refkit,intel/intel-iot-refkit,mythi/intel-iot-refkit,YinThong/intel-iot-refkit,ipuustin/intel-iot-refkit,ipuustin/intel-iot-refkit,YinThong/intel-iot-refkit,YinThong/intel-iot-refkit,YinThong/intel-iot-refkit,YinThong/intel-iot-refkit,ipuustin/intel-iot-refkit,jairglez/intel-iot-refkit,YinThong/intel-iot-refkit,intel/intel-iot-refkit,jairglez/intel-iot-refkit,klihub/intel-iot-refkit,jairglez/intel-iot-refkit,mythi/intel-iot-refkit,intel/intel-iot-refkit,jairglez/intel-iot-refkit,klihub/intel-iot-refkit,ipuustin/intel-iot-refkit,mythi/intel-iot-refkit,ipuustin/intel-iot-refkit,intel/intel-iot-refkit,jairglez/intel-iot-refkit,klihub/intel-iot-refkit,ipuustin/intel-iot-refkit,mythi/intel-iot-refkit,klihub/intel-iot-refkit