The semaphore `stats_collector` references is the one obtained from the database object, which is already stopped by `database::stop()`, making the stop in `~stats_collector()` redundant, and even worse, as it triggers an assert failure. Remove it. Signed-off-by: Botond Dénes <bdenes@scylladb.com> Message-Id: <20210518140913.276368-1-bdenes@scylladb.com>