How do I calculate the total resistance of this potentiometer circuit?
Assuming you want the resistance at the two wires, yes, R2.2 is shorted out (in parallel with zero).
It's completely bypassed. 

Therefore total resistance (when switch is closed) is:

Rt = R2.1 + R3//RB               [ // symbol for 'in parallel']
Rt = R2.1 + (R3*RB/(R3+RB))

If you want the resistance across UB, then just ignore R2.1 and work out R3//RB.