title: invoke gradle in jenkins pipeline
body: <p>I am trying to use gradle in jenkins pipeline. The build fails with error "Task clean not found in root project 'pipe1'"</p>
  
  <p>Installed jenkins on centos</p>
  
  <p>pipeline {
      agent any
      stages{
          stage('source') {
              steps {
                  git '<a href="https://github.com/javahometech/my-app.git" rel="nofollow noreferrer">https://github.com/javahometech/my-app.git</a>'
              }
          }
          stage('compile') {
              tools {
                  gradle 'gradle3'
              }
              steps {
                  sh 'gradle clean compile'
              }
          }
      }
  }</p>
  
  <p>build fails with error</p>
  
  <p>Starting a Gradle Daemon (subsequent builds will be faster)</p>
  
  <p>FAILURE: Build failed with an exception.</p>
  
  <ul>
  <li>What went wrong:
  Task 'clean' not found in</li>
  </ul>