Don't mark a previously completed mission as incomplete, upon replay failure.

src/battle/battle.c

@@ -437,7 +437,7 @@ static void postBattle(void)
 
 	updateAccuracyStats(game.stats);
 	
-	game.currentMission->completed = (battle.status == MS_COMPLETE || !battle.numObjectivesTotal);
+	game.currentMission->completed = (game.currentMission->completed || battle.status == MS_COMPLETE || !battle.numObjectivesTotal);
 	
 	app.saveGame = 1;
 }