Switch to disable caching of list-items, or override latency threshold

Kodi caches list-items for anything that takes more than 1000ms. In Kodi 17 a bug was introduced and these caches don’t get invalidated, causing wrong result to be displayed.

If fixing that is too much trouble, would it be possible to make this 1000ms something configurable via advancedsettings so that those of us using MySQL can enjoy Kodi 17?