There was some unreachable code in dokick related to drawbridges. Since I
liked the current "Ouch!" behavior, I moved the drawbridge test inside the
IS_STWALL code but made sure to update the maploc so kickstr would return
the right thing. Since there may be more than one drawbridge (perhaps it
should test for Valkyrie?) changed the kickstr prefix for drawbridge to "a".
2d8bc8875e