searchengine: Avoid criticals when tracker init failed
Those criticals:
Tracker-CRITICAL **: 10:05:59.634: tracker_sparql_connection_close: assertion 'TRACKER_IS_SPARQL_CONNECTION (connection)' failed
Gtk-CRITICAL **: 10:05:59.634: Could not init tracker3 search engine: The name org.freedesktop.Tracker3.Miner.Files was not provided by any .service files
Edited by Gaël Bonithon