made esi service public

src/Symfony/Bundle/FrameworkBundle/Resources/config/esi.xml

@@ -10,7 +10,7 @@
     </parameters>
 
     <services>
-        <service id="esi" class="%esi.class%" public="false" />
+        <service id="esi" class="%esi.class%" />
 
         <service id="esi_listener" class="%esi_listener.class%">
           <tag name="kernel.listener" event="onCoreResponse" />