Remove buffered writes from memcache example

They seem to cause trouble, also inconsistent behaviour between versions of the memcached extension.

config-templates/config.php

@@ -675,7 +675,6 @@ $config = [
      *              \Memcached::OPT_NO_BLOCK => true,
      *              \Memcached::OPT_TCP_NODELAY => true,
      *              \Memcached::OPT_LIBKETAMA_COMPATIBLE => true,
-     *              \Memcached::OPT_BUFFER_WRITES => true,
      *         ],
      *         ['hostname' => '127.0.0.1', 'port' => 11211],
      *         ['hostname' => '127.0.0.2', 'port' => 11211],
@@ -687,7 +686,6 @@ $config = [
      *              \Memcached::OPT_NO_BLOCK => true,
      *              \Memcached::OPT_TCP_NODELAY => true,
      *              \Memcached::OPT_LIBKETAMA_COMPATIBLE => true,
-     *              \Memcached::OPT_BUFFER_WRITES => true,
      *         ],
      *         ['hostname' => '127.0.0.3', 'port' => 11211],
      *         ['hostname' => '127.0.0.4', 'port' => 11211],