swarm, cmd/swarm: address ineffectual assignments (#18048)

* swarm, cmd/swarm: address ineffectual assignments

* swarm/network: remove unused vars from testHandshake

* swarm/storage/feed: revert cursor changes

swarm/network/stream/syncer_test.go

@@ -62,6 +62,9 @@ func createMockStore(globalStore *mockdb.GlobalStore, id enode.ID, addr *network
 	params.Init(datadir)
 	params.BaseKey = addr.Over()
 	lstore, err = storage.NewLocalStore(params, mockStore)
+	if err != nil {
+		return nil, "", err
+	}
 	return lstore, datadir, nil
 }