title: Azure login with Jenkins pipeline
body: <p>I'm trying to login to Azure using Azure Credentials plugin via Jenkins pipeline (Ubuntu 16.04 as Jenkins slave with the latest Azure CLI):</p>
  
  <pre><code> stage("Pushing to Azure Storage") {
              withCredentials([azureServicePrincipal(credentialsId: 'AzureServicePrincipal',
                                      subscriptionIdVariable: 'SUBS_ID',
                                      clientIdVariable: 'CLIENT_ID',
                                      clientSecretVariable: 'CLIENT_SECRET',
                                      tenantIdVariable: 'TENANT_ID')]) {
          sh 'az login --service-principal -u $CLIENT_ID -p $CLIENT_SECRET -t $TENANT_ID'
      }
  }
  </code></pre>
  
  <p>The results is the following error:</p>
  
  <blockquote>
    <p><strong>*[PushTest] Running shell script
    +az login --service-principal -u **** -p **** -t **** /tmp/jenkins/workspace/PushTest@tmp/durable-7425816d/script.sh: 2:
    /tmp/jenkins/workspace/PushTest@tmp/durable-7425816d/script.sh: az:
    not found*</strong></p>
    
    <p><strong>script returned exit code 127</strong></p>
  </blockquote>