Allow DEBUGging of the run_tests.sh script (and maybe more)

Change-Id: I25adb0966574bdac05ea0608b73656d07f14eacf
diff --git a/jenkins/client/job/debian/packages/salt-multi.yml b/jenkins/client/job/debian/packages/salt-multi.yml
index 90e6f02..f7a87c7 100644
--- a/jenkins/client/job/debian/packages/salt-multi.yml
+++ b/jenkins/client/job/debian/packages/salt-multi.yml
@@ -142,3 +142,6 @@
               UPLOAD_APTLY:
                 type: boolean
                 default: '{{upload_source_package}}'
+              DEBUG:
+                type: boolean
+                default: 'false'