[bug-OpenMage#107] getCommentText() for <groups> in system.xml not su…

…pported

In system.xml <comment> has a diffent behavior for <fields> and <groups>.
This only works for <fields>:

```
<comment>
    <model>namespace/module<model>
</comment>
```

app/code/core/Mage/Adminhtml/Block/System/Config/Form.php

@@ -193,7 +193,7 @@ protected function _initGroup($form, $group, $section, $parentElement = null)
             $helperName = $this->_configFields->getAttributeModule($section, $group);
             $fieldsetConfig = array('legend' => Mage::helper($helperName)->__((string)$group->label));
             if (!empty($group->comment)) {
-                $fieldsetConfig['comment'] = Mage::helper($helperName)->__((string)$group->comment);
+                $fieldsetConfig['comment'] = $this->_prepareGroupComment($group, $helperName);
             }
             if (!empty($group->expanded)) {
                 $fieldsetConfig['expanded'] = (bool)$group->expanded;
@@ -525,6 +525,18 @@ protected function _prepareFieldComment($element, $helper, $currentValue)
         return $comment;
     }
 
+    /**
+     * Support models "getCommentText" method for group note generation
+     *
+     * @param Mage_Core_Model_Config_Element $element
+     * @param string $helper
+     * @return string
+     */
+    protected function _prepareGroupComment($element, $helper)
+    {
+        return $this->_prepareFieldComment($element, $helper, null);
+    }
+
     /**
      * Prepare additional comment for field like tooltip
      *