I started to add handling for doorways containing mimic-as-boulder
to doopen() and doclose() as was done for pick_lock(), but decided that
it was better just to prevent mimics from appearing as boulders at closed
door locations in the first place. So the most recent pick_lock() change
and its fixes entry go away.
This also fixes a post-3.4.3 bug. On the top level of Sokoban I
discovered a boulder over a hole; probing reported it as a mimic with
0 hp. The special level loading code moves mimic-as-boulder away from
trap spots by using place_monster() to put it on another spot, but it
was missing the corresponding remove_monster() to take it away from the
original location so left a stale pointer on the map.
3b6c59c7fc