Fixed EZEE-1864: Set ezpublish.cache_pool Service to be lazy (#2305)

When building Symfony DI Container, CachePool is created from factory
prior to setting SiteAccess-aware context, however it depends on
SA setting for Persistence Cache Service (Filesystem, Redis, Memcached)

eZ/Bundle/EzPublishCoreBundle/Resources/config/cache.yml

@@ -17,6 +17,7 @@ services:
     # in Core configuration, see eZ/Publish/Core/settings/storage_engines/cache.yml for details
     ezpublish.cache_pool:
         class: "%ezpublish.cache_pool.class%"
+        lazy: true
         factory: ["@ezpublish.cache_pool.factory", getCachePool]
         arguments: ["@ezpublish.config.resolver"]