fixes issue #ZF-8036. allows for '0' or ' ' empty string title.

git-svn-id: http://framework.zend.com/svn/framework/standard/trunk@18575 44c647ce-9c0f-0410-b52a-842ac1e357ba

library/Zend/View/Helper/HeadTitle.php

@@ -63,7 +63,8 @@ class Zend_View_Helper_HeadTitle extends Zend_View_Helper_Placeholder_Container_
      */
     public function headTitle($title = null, $setType = Zend_View_Helper_Placeholder_Container_Abstract::APPEND)
     {
-        if ($title) {
+    	$title = (string) $title;
+        if ($title !== '') {
             if ($setType == Zend_View_Helper_Placeholder_Container_Abstract::SET) {
                 $this->set($title);
             } elseif ($setType == Zend_View_Helper_Placeholder_Container_Abstract::PREPEND) {