NullPointerException in SourceHasCounterCondition

Log from alpha:

```
java.lang.NullPointerException
at mage.counters.Counters.getCount(Counters.java:73)
at mage.abilities.condition.common.SourceHasCounterCondition.apply(SourceHasCounterCondition.java:64)
at mage.abilities.decorator.ConditionalAsThoughEffect.applies(ConditionalAsThoughEffect.java:83)
at mage.abilities.effects.ContinuousEffects.asThough(ContinuousEffects.java:573)
at mage.game.permanent.PermanentImpl.canAttackInPrinciple(PermanentImpl.java:1520)
at mage.game.permanent.PermanentImpl.canAttack(PermanentImpl.java:1481)
at mage.players.PlayerImpl.lambda$getAvailableAttackers$11(PlayerImpl.java:3503)
at java.util.ArrayList.removeIf(ArrayList.java:1415)
at mage.players.PlayerImpl.getAvailableAttackers(PlayerImpl.java:3503)
at mage.players.PlayerImpl.getAvailableAttackers(PlayerImpl.java:3496)
at mage.game.combat.Combat.checkAttackRequirements(Combat.java:476)
at mage.game.combat.Combat.selectAttackers(Combat.java:266)
at mage.game.turn.DeclareAttackersStep.beginStep(DeclareAttackersStep.java:36)
at mage.game.turn.Phase.prePriority(Phase.java:189)
at mage.game.turn.Phase.playStep(Phase.java:203)
at mage.game.turn.Phase.play(Phase.java:91)
at mage.game.turn.Turn.play(Turn.java:129)
at mage.game.GameImpl.playTurn(GameImpl.java:1157)
at mage.game.GameImpl.play(GameImpl.java:1064)
at mage.game.GameImpl.start(GameImpl.java:1040)
at mage.server.game.GameWorker.call(GameWorker.java:35)
at mage.server.game.GameWorker.call(GameWorker.java:16)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:750)
```