cluster-cache: fix init function setting memcache count instead of memcache max

src/cluster-cache.c

@@ -44,7 +44,7 @@ enum ec3_status cluster_cache_init(
 		}
 	}
 
-	out->c_memcache_count = 4;
+	out->c_memcache_max = 4;
 	out->c_cluster_size = cluster_size;
 	return EC3_SUCCESS;
 }