Dan, the liberal party was looking like it would losing the next election with Abbott was leader and they decided not to take that risk.
You may think that Abbott could have won the next election but I would say the liberal party had a better understanding of their position. It would not have been a decision taken lightly given what was at stake.
So you will vote for some minor party or none at all, really doesn't matter because the Turnbull government will get over the line with ease