Previously we were checking l->data != NULL || (l->data != NULL &&
l->data != priv->current_effect). This would continue the loop even
if l->data == priv->current_effect, since l->data != NULL, which was
not the intention of that loop.
We also don't need to check that l->data != NULL before checking if
it does not match the current_effect, since we already checked
that current_effect was non-NULL before entering the loop.
4270eef16e