system distributed keyspace: Start sharded service erarlier

The constructors just set up the references, real start happens in .start()
so it is safe to do this early. This helps not carrying migration manager
and query processor down the storage service cluster joining code.

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

main.cc

@@ -1071,6 +1071,8 @@ int main(int ac, char** av) {
                 gms::stop_gossiping().get();
             });
 
+            sys_dist_ks.start(std::ref(qp), std::ref(mm)).get();
+
             ss.init_server().get();
             sst_format_selector.sync();
             ss.join_cluster().get();

service/storage_service.cc

@@ -391,7 +391,6 @@ void storage_service::prepare_to_join(
 
 void storage_service::maybe_start_sys_dist_ks() {
     supervisor::notify("starting system distributed keyspace");
-    _sys_dist_ks.start(std::ref(cql3::get_query_processor()), std::ref(service::get_migration_manager())).get();
     _sys_dist_ks.invoke_on_all(&db::system_distributed_keyspace::start).get();
 }
 

test/lib/cql_test_env.cc

@@ -561,6 +561,8 @@ public:
             db::system_keyspace::init_local_cache().get();
             auto stop_local_cache = defer([] { db::system_keyspace::deinit_local_cache().get(); });
 
+            sys_dist_ks.start(std::ref(qp), std::ref(mm)).get();
+
             service::get_local_storage_service().init_server(service::bind_messaging_port(false)).get();
             service::get_local_storage_service().join_cluster().get();