Follows-up 192d37b19a.
So we can turn them off in preparation of Gadgets 2.0, which
doesn't support them at all.
Change-Id: I98b4146579ccbbfcad8b83a51cc095da1fad673c
Add a configuration option, 'GadgetsCacheType', which may be used to specify
the ObjectCache type to use for gadget definitions.
Change-Id: I1e02f7b6c470c5fffa014c6247c71f43a69420b6