title: woocommerce_order_status_completed not called on stripe payment
body: <p>I have written a custom plugin and part of this plug in uses the "woocommerce_order_status_completed" hook as:</p>
  
  <pre><code>add_action( 'woocommerce_order_status_completed', 'mmd_woointerface_order_complete', 1);
  mmd_woointerface_order_complete($order)
  {
   //print to log file here
  }
  </code></pre>
  
  <p>I am using the stripe payment system and have checked and double checked the API Keys, have defined the Webhook end points as recommended by the woocommerce plugins.</p>
  
  <ol>
  <li>I tried making a purchase and the system seem to respond correctly, with orders showing up in the backend of my site.  </li>
  <li>I have tried sending test webhooks using the strip backend.</li>
  </ol>
  
  <p>None of these options cause the <strong>mmd_woointerface_order_complete</strong>, action to performed.  My custom call is never initiated.  Am I missing something.  </p>
  
  <p>Has any one got this to work with Stripe? Need help.</p>