title: woocommerce_add_order_item_meta hook sending only one argument; three expected
body: <p>I am using WC v. 2.3.9.</p>
  
  <p>woocommerce_add_order_item_meta gets fired but my callback function only gets one parameter, three expected.</p>
  
  <p>I want to add order item meta at the creation of the order.</p>
  
  <p>Is this hook really available? Some rumour say that it's deprecated.</p>
  
  <p><strong><em>Edit : after a few research it's the function woocommerce_add_order_item_meta() that is deprecated.</em></strong></p>
  
  <p>Anyway I can find it in woocommerce/includes/class-wc-checkout.php. And the "do_action()" on this hook seems straightforward:</p>
  
  <pre><code>// Store the line items to the new/resumed order
  foreach ( WC()-&gt;cart-&gt;get_cart() as $cart_item_key =&gt; $values ) {
     $item_id = $order-&gt;add_product(
      $values['data'],
      $values['quantity'],
      array(
         'variation' =&gt; $values['variation'],
         'totals'    =&gt; array(
         'subtotal'     =&gt; $values['line_subtotal'],
         'subtotal_tax' =&gt; $values['line_subtotal_tax'],
         'total'        =&gt; $values['line_total'],
         'tax'          =&gt; $values['line_tax'],
         'tax_data'     =&gt; $values['line_tax_data'] // Since 2.2
      )
        )
  );
     if ( ! $item_id ) {
        throw new Exception( sprintf( __( 'Error %d: Unable to create order. Please try again.', 'woocommerce' ), 402 ) );
     }
     // Allow plugins to add order item meta
     do_action( 'woocommerce_add_order_item_meta', $item_id, $values, $cart_item_key );
  }
  </code></pre>
  
  <p>my custom plugin code:</p>
  
  <pre><code>public function __construct(){
     add_action('woocommerce_add_order_item_meta', array($this, 'charlie_ajoute_un_order_item_meta'));
  }
  
  public function charlie_ajoute_un_order_item_meta($item_id, $values, $cart_item_key){
     if (isset($values['cred_meta']['cred_post_id'])){
        $annonce_id = $values['cred_meta']['cred_post_id'];
     }
     elseif(isset($values['annonce_concernee'])){
        $annonce_id = $values['annonce_concernee'];
     }
     else{
        $annonce_id = 'turlututu';
  /* as $values as well as $$cart_item_key are not set, my order item meta is always "turlututu".*/
     }
     wc_add_order_item_meta( $item_id, 'annonce_concernee', $annonce_id, true );
  }
  </code></pre>
  
  <p>Thanks for your help !</p>
  
  <p>Charles</p>