Fix restore from context settings in Discretize widget.
Fix restore from context settings in Discretize widget.

Purge the restored variable states of Default discretization states
(use the current selected default instead). Before the GUI and the
actual discretization settings would be left in an inconsistent state.

kwikadi/orange3,marinkaz/orange3,qPCR4vir/orange3,cheral/orange3,kwikadi/orange3,marinkaz/orange3,kwikadi/orange3,qPCR4vir/orange3,cheral/orange3,kwikadi/orange3,cheral/orange3,marinkaz/orange3,kwikadi/orange3,cheral/orange3,kwikadi/orange3,marinkaz/orange3,marinkaz/orange3,qPCR4vir/orange3,marinkaz/orange3,qPCR4vir/orange3,qPCR4vir/orange3,cheral/orange3,cheral/orange3,qPCR4vir/orange3