Fix DiscreteVariable.find_compatible not to fail when there are no existing variables with this name
Fix DiscreteVariable.find_compatible not to fail when there are no existing variables with this name

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