execute commands using bash

Change-Id: I594eb5462cce4ca33a99909889a7c46d62fe376d
diff --git a/Jenkinsfile b/Jenkinsfile
index de85c49..3ee98d0 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -4,7 +4,9 @@
     stages {
         stage('build') {
             steps {
-                bash '. tools/build/envDefaults && onos-buck build onos'
+                sh '''#!/bin/bash -l
+                . tools/build/envDefaults && onos-buck build onos'
+                '''
             }
         }
     }