Implement a fix for the problem From a bug report:
if the destination position on the Plane of Fire has a randomly
placed trap on it, you'd get an impossibility warning of "couldn't
place lregion type 5" (and then arrive successfully at the target
spot anyway). As his investigation indicated, the code to remove
such traps wasn't being reached because the `bad_location' check
yields true for trapped spots.
SPLEVTYPE can have a value like "minetn-3,minend-2,soko2-2" and allows
someone in debug mode to select specific instances of random levels to use
in a test game. Invalid values found in SPLEVTYPE are silently ignored.
