WIXBUG:4472

Try to clean the downloaded update bundle from the cache.
I'm ok with this as long as we do the second half of the change which is to add:

            // Prevent this package from being cleaned if we actually Plan an UpdateReplace.
            m_pEngineState->update.package.cacheType = BURN_CACHE_TYPE_YES;

inside of EngineForApplication.cpp, in SetUpdate after PseudoBundleInitialize.