run-uninstalled script requires Tracker to be installed

The new run-uninstalled script actually requires you to have Tracker installed to do certain things, because libtracker-control expects to read the miner .service files from $prefix/share/tracker/miners. It doesn't know how to find them in the build tree.

The best fix is probably to add another environment variable, maybe TRACKER_MINER_SERVICE_DIR, so the ./run-uninstalled script can point it to a directory inside the build tree.