Revert "ModuleActionController: fix forward/X-Icinga-Module"

This reverts commit bf82bd4ce1.

We have a not merged branch for this.

refs #9349

library/Icinga/Web/Controller/ModuleActionController.php

@@ -73,6 +73,6 @@ class ModuleActionController extends ActionController
     public function postDispatchXhr()
     {
         parent::postDispatchXhr();
-        $this->getResponse()->setHeader('X-Icinga-Module', $this->moduleName, true);
+        $this->getResponse()->setHeader('X-Icinga-Module', $this->moduleName);
     }
 }