montraits vs monst->mstate

The new test in m_detach(mon) to check whether mon was already detached
is being tripped for trolls who died, revived, and died again.  Clear
out the MON_DETACH bit when saving montraits.

src/cmd.c

@@ -1018,6 +1018,8 @@ makemap_unmakemon(struct monst *mtmp, boolean migratory)
            so that dmonsfree() bookkeeping for number of dead or removed
            monsters won't get out of sync; it is not on the map but
            mongone() -> m_detach() -> mon_leaving_level() copes with that */
+        mtmp->mstate |= MON_OFFMAP;
+        mtmp->mstate &= ~(MON_MIGRATING | MON_LIMBO);
         mtmp->nmon = fmon;
         fmon = mtmp;
     }

src/mkobj.c

@@ -1982,6 +1982,7 @@ save_mtraits(struct obj *obj, struct monst *mtmp)
             mtmp2->mhp = mtmp2->mhpmax;
         if (mtmp2->mhp < 1)
             mtmp2->mhp = 0;
+        mtmp2->mstate &= ~MON_DETACH;
     }
     return obj;
 }