Update Jenkinsfile

err at the catch was duplicate local variable  and caused compile error

Author: andrask

jenkinsfile-examples/nodejs-build-test-deploy-docker-notify/Jenkinsfile

@@ -27,7 +27,6 @@ THE SOFTWARE.
 node('node') {
 
 
-    def err = null
     currentBuild.result = "SUCCESS"
 
     try {