when our lock-on target goes invalid clear the target so we don't keep tracking her.
when our lock-on target goes invalid clear the target so we don't keep tracking her.

kongr45gpen/bzflag-import-1,kongr45gpen/bzflag-import-1,kongr45gpen/bzflag-import-1,kongr45gpen/bzflag-import-1,kongr45gpen/bzflag-import-1,kongr45gpen/bzflag-import-1