The gossiper verbs are registered in two places -- start_gossiping
and do_shadow_round(). And unregistered in one -- stop_gossiping
iff the start took place. Respectively, there's a chance that after
a shadow round scylla exits without starting gossiping thus leaving
verbs armed.
Fix by unregistering verbs on stop if they are still registered.
fixes: #7262
tests: manual(start, abort start after shadow round), unit(dev)
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Message-Id: <20200921140357.24495-1-xemul@scylladb.com>