storage_service: Remove _ms_stopped

This boolean protects do_stop_ms from re-entrability. However, this
method is only called from stop_transport() which handles re-entring
itself, so the _ms_stopped can be just removed.

Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>

service/storage_service.cc

@@ -1781,10 +1781,6 @@ future<> storage_service::stop_gossiping() {
 }
 
 future<> storage_service::do_stop_ms() {
-    if (_ms_stopped) {
-        return make_ready_future<>();
-    }
-    _ms_stopped = true;
     return _messaging.invoke_on_all([] (auto& ms) {
         return ms.shutdown();
     }).then([] {

service/storage_service.hh

@@ -152,7 +152,6 @@ private:
     sharded<repair_service>& _repair;
     sharded<streaming::stream_manager>& _stream_manager;
     sstring _operation_in_progress;
-    bool _ms_stopped = false;
     seastar::metrics::metric_groups _metrics;
     using client_shutdown_hook = noncopyable_function<void()>;
     std::vector<protocol_server*> _protocol_servers;