I suppose you can file a motion to quash, but now you'll need to submit evidence that you no longer control those Bitcoins. Good luck. Maybe you'll say the passphrase was destroyed. You might be lying, but in any case, they're as good as seized, because if the Bitcoins are ever spent, we'll see it in the blockchain.
And that's all assuming that the loss or destruction of the Bitcoins even matters to the court. Maybe the current USD value of N BTC is just added to your non-dischargeable debt.
Bitcoins raise some interesting legal & law enforcement questions, but it's wrong to assume that they somehow exempt their users from the law, or prevent all enforcement of the law.
People have been trying to bypass the law for millennia, and it rarely works: The law just isn't that fragile.