`tracker-sandbox --update` should wait for extraction to complete
The sandbox script runs
tracker-miners-fs --no-daemon to index the content that it's given. This means that indexing runs in the foreground and the script exits as soon as it is finished. However, currently
tracker-miner-fs --no-daemon doesn't start the extractor, which makes the whole thing a bit useless.
I think we should modify
tracker-miner-fs --no-daemon so that it waits for extraction to finish before exiting.