Fixed wrong method name

git-svn-id: http://framework.zend.com/svn/framework/standard/trunk@21145 44c647ce-9c0f-0410-b52a-842ac1e357ba

documentation/manual/en/module_specs/Zend_Http_Client-Adapters.xml

@@ -664,7 +664,7 @@ $client = new Zend_Http_Client('http://www.example.com', array(
 ));
 
 // Force the next request to fail with an exception
-$adapter->nextRequestWillFail(true);
+$adapter->setNextRequestWillFail(true);
 
 try {
     // This call will result in a Zend_Http_Client_Adapter_Exception