stream-restore: Clear the save_sink/save_source flags on apply_entry.

stream-restore: Clear the save_sink/save_source flags on apply_entry.

If the user specifically removes the device element from the stream
restore rule, we have to clear the save_sink/save_source flag of the
stream. This means that other stream routing systems
(e.g. module-device-manager) can take over routing for this
stream. In order to facilitate the reapplication of other routing
rules, we fire a stream change event. Arguably the stream itself
has not changed, but the rules governing its routing have, so
I feel this is justified.