Improved error handling in test pipelines.

Change-Id: Iecd0451fa776c2238e65672269c1ac2a6c734baf
diff --git a/test-system-reclass-pipeline.groovy b/test-system-reclass-pipeline.groovy
index a63a7df..65fce27 100644
--- a/test-system-reclass-pipeline.groovy
+++ b/test-system-reclass-pipeline.groovy
@@ -57,7 +57,7 @@
         }
       parallel branches
     }else{
-       common.errorMsg("Cannot checkout gerrit patchset, GERRIT_REFSPEC and DEFAULT_GIT_REF is null")
+       throw new Exception("Cannot checkout gerrit patchset, GERRIT_REFSPEC and DEFAULT_GIT_REF is null")
     }
   }
 } catch (Throwable e) {