simplified some code

lib/Twig/Environment.php

@@ -989,9 +989,7 @@ class Twig_Environment
             if (!array_key_exists($name, $this->globals)) {
                 throw new LogicException(sprintf('Unable to add global "%s" as the runtime or the extensions have already been initialized.', $name));
             }
-        }
 
-        if ($this->extensionInitialized || $this->runtimeInitialized) {
             // update the value
             $this->globals[$name] = $value;
         } else {