kvdb/etcd: replace defer cleanup with t.Cleanup

Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>

kvdb/etcd/readwrite_tx_test.go

@@ -15,7 +15,6 @@ func TestChangeDuringManualTx(t *testing.T) {
 	t.Parallel()
 
 	f := NewEtcdTestFixture(t)
-	defer f.Cleanup()
 
 	db, err := newEtcdBackend(context.TODO(), f.BackendConfig())
 	require.NoError(t, err)
@@ -44,7 +43,6 @@ func TestChangeDuringUpdate(t *testing.T) {
 	t.Parallel()
 
 	f := NewEtcdTestFixture(t)
-	defer f.Cleanup()
 
 	db, err := newEtcdBackend(context.TODO(), f.BackendConfig())
 	require.NoError(t, err)