hmon() arg fix

The call to hmon() in flooreffects() was passing a boolean where int
is expected.  The 'thrown' argument may have once been a boolean, but
it is 'int' for as far back as the repository history goes.

src/do.c

@@ -159,7 +159,9 @@ const char *verb;
             if (mtmp) {
                 if (!passes_walls(mtmp->data) && !throws_rocks(mtmp->data)) {
                     int dieroll = rnd(20);
-                    if (hmon(mtmp, obj, TRUE, dieroll) && !is_whirly(mtmp->data))
+
+                    if (hmon(mtmp, obj, HMON_THROWN, dieroll)
+                        && !is_whirly(mtmp->data))
                         return FALSE; /* still alive */
                 }
                 mtmp->mtrapped = 0;