Add failFast option for parallel builds for salt-ci-wrapper

Change-Id: Ifb946eeae3873d87933704d3c7413ef9ecaf460f
diff --git a/test-salt-model-wrapper.groovy b/test-salt-model-wrapper.groovy
index c1cee0a..9f61db8 100644
--- a/test-salt-model-wrapper.groovy
+++ b/test-salt-model-wrapper.groovy
@@ -167,6 +167,7 @@
             }
 
             def branches = [:]
+            branches.failFast = true
             String branchJobName = ''
 
             if (gerritProject == reclassSystemRepo && gerritBranch == 'master') {