add email notification to nightly build failure

Author: ddsharpe

Jenkinsfile

@@ -83,6 +83,11 @@ pipeline {
                 always {
                     junit 'tests/target/failsafe-reports/*.xml'
                 }
+                failure {
+                    mail to: "${env.WIT_BUILD_NOTIFICATION_EMAIL_TO}", from: 'noreply@oracle.com',
+                    subject: "WebLogic Image Tool: ${env.JOB_NAME} - Failed",
+                    body: "Job Failed - \"${env.JOB_NAME}\" build: ${env.BUILD_NUMBER}\n\nView the log at:\n ${env.BUILD_URL}\n"
+                }
             }
         }
      }