Fix pet location inconsistency

... if the pet attacked hero or another monster by eg.
swallowing them, the pet's location might've changed
during that attack. Count it as movement, so return
immediately.

src/dogmove.c

@@ -1181,6 +1181,10 @@ int after; /* this is extra fast monster movement */
                     }
                 }
             }
+
+            /* pet moved when attacking */
+            if (mtmp->mx != omx || mtmp->my != omy)
+                return 0;
         }
     }