Add path to validate_manifest.sh

Change-Id: I1be75f514857e720c6b78d388b15046e1ff75493
diff --git a/Jenkinsfile b/Jenkinsfile
index 03402b4..117f70c 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -28,7 +28,7 @@
 }
 
 def validateXMLwithDTD() {
-    sh returnStdout: true, script: 'validate_manifest.sh'
+    sh returnStdout: true, script: './validate_manifest.sh'
 }
 
 int checkBranchExists(def proj) {