Load all child blocks in Adminhtml Head block (#3222)

Author: elidrissidev

app/design/adminhtml/default/default/template/page/head.phtml

@@ -50,5 +50,4 @@
 </script>
 
 <?php echo $this->helper('core/js')->getTranslatorScript() ?>
-<?php echo $this->getChildHtml('calendar'); ?>
-<?php echo $this->getChildHtml('optional_zip_countries'); ?>
+<?php echo $this->getChildHtml(); ?>