fixed Lsw\MemcacheBundle\Cache\LoggingMemcache

ContextErrorException: Notice: Undefined property: Lsw\MemcacheBundle\Cache\AntiDogPileMemcache::$memcache in [...]/vendor/leaseweb/memcache-bundle/Lsw/MemcacheBundle/Cache/LoggingMemcache.php line 518