backward compatibility

[LukasT.dev@gmail.com]

> ...Or did I miss something? 

There are two stages when loading the presets. One for the paintop and one for 
the GUI widgets.

I did the check when the paintop is loading the preset in 
KisDeformPaintOpSettings. But the GUI part of the paintop has also code for 
loading the preset. The airbrush option loads the preset at 
KisAirbrushOption::readOptionSetting(). That class is part of the library and 
does not know about deform brush (and it's presets strings).

I could hardcode DEFORM_USE_MOVEMENT_PAINT there so that the GUI is setup 
correctly in the deform brush case. But I don't think it's nice.