protected method being called

During the tidy up the methods doDirectPayment & doDirectTransfer were changed to protected.

Since I actually advocate using doPayment rather than either of those 2 I am submitting a patch for making that change rather than switching back.

This isn't the only instance where it happens but it doesn't seem to cause e-notices - just big red alerts in phpstorm. However, since I'm writing custom code to alter this particular form at the moment I feel like I've tested the change in this location to be worth a PR on it.

NB - the reason I advocate doPayment over the others is that the labels don't really reflect 'today's processors' & the form doesn't really need to know what the method is anyway.

Will submit against master since no apparent enotices