Fix Symfony deprecation notice

Author: mpdude

Resources/config/services.xml

@@ -44,9 +44,8 @@
         </service>
 
         <service id="webfactory_legacy_integration.xpath_helper"
-                 class="Webfactory\Bundle\LegacyIntegrationBundle\Integration\XPathHelper"
-                 factory-service="webfactory_legacy_integration.xpath_helper_factory"
-                 factory-method="createHelper">
+                 class="Webfactory\Bundle\LegacyIntegrationBundle\Integration\XPathHelper">
+            <factory service="webfactory_legacy_integration.xpath_helper_factory" method="createHelper" />
         </service>
 
     </services>

composer.json

@@ -18,7 +18,7 @@
 
     "require": {
         "symfony/framework-bundle": "~2.2",
-        "symfony/dependency-injection": "~2.2",
+        "symfony/dependency-injection": "~2.6",
         "symfony/config": "~2.2",
         "symfony/http-kernel": "~2.2",
         "symfony/http-foundation": "~2.2",