[05aac56] Shock attacks can go through shock immunity

Shocking attacks such as from skitterbots can still hurt you even if you have immunity to shocking attacks, the message “The %s unsuccessfully attempts to shock you.” appears, then right after “The %s shocks you!” appears and you take random damage.

The bug is at line 2583 of monattack.cpp, seems like it should be an else if statement there.