metalua: add test

Closes #28518.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
memcached 1.4.18
Removing older bottles for memcached 1.4.17
Revert "Removing older bottles for memcached 1.4.17"

This reverts commit 9293e529ece01e2741543d09df371200a7749624.
memcached: update 1.4.18 bottle.