The settings cache used in RequestInformation was never overwritten. Therefore,
user settings were ignored after setting AutoDetect, calling
RequestInformation and then turning AutoDetect off. This is a common pattern
in ParaView since it calls RequestInformation with default settings in order
to get array names. Fixed by deleting the cache when the object is modified.

Change-Id: Ibc832726cf1ba8a5839770eae5fae2b893c00357