bug #4012 Fix xml route configuration for routing condition (xavierbriand)

This PR was submitted for the master branch but it was merged into the 2.4 branch instead (closes #4012).

Discussion
----------

Fix xml route configuration for routing condition

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.4+
| Fixed tickets |  #4011

Commits
-------

6790fb2 Fix xml route configuration for routing condition

Author: weaverryan

book/routing.rst

@@ -758,11 +758,9 @@ can be extended to have an almost infinite flexibility using ``conditions``:
             xsi:schemaLocation="http://symfony.com/schema/routing
                 http://symfony.com/schema/routing/routing-1.0.xsd">
 
-            <route id="contact"
-                path="/contact"
-                condition="context.getMethod() in ['GET', 'HEAD'] and request.headers.get('User-Agent') matches '/firefox/i'"
-            >
+            <route id="contact" path="/contact">
                 <default key="_controller">AcmeDemoBundle:Main:contact</default>
+                <condition>context.getMethod() in ['GET', 'HEAD'] and request.headers.get('User-Agent') matches '/firefox/i'</condition>
             </route>
         </routes>