RemoveOrder doesn't find the order

[moshababo]

From xud-simulation:

08/02/2019 09:55:54.806 [RPC] debug: received call /xudrpc.Xud/PlaceOrderSync
08/02/2019 09:55:54.808 [ORDERBOOK] debug: order added: {"pairId":"LTC/BTC","price":10,"quantity":10,"isBuy":true,"localId":"random_order_id","hold":0,"id":"f6314470-2b76-11e9-9d4b-2144188b75ef","initialQuantity":10,"createdAt":1549612554807}
08/02/2019 09:55:54.814 [RPC] debug: received call /xudrpc.Xud/GetInfo
08/02/2019 09:55:54.821 [RPC] debug: received call /xudrpc.Xud/GetInfo
08/02/2019 09:55:56.225 [RPC] debug: received call /xudrpc.Xud/RemoveOrder
08/02/2019 09:55:56.227 [ORDERBOOK] error: attempted to remove non-existing orderId (f6314470-2b76-11e9-9d4b-2144188b75ef)

The issue was introduced by this commit: e46d55d

In addition, the response to RemoveOrder doesn't return an error, and so the error was silent. This problem existed before - removeOwnOrderByLocalId doesn't throw an error when removeOwnOrder fails and returns false. The later can be changed to throw an error instead of returning a boolean.

[kilrau]

Since it was your commit - are you taking care? @sangaman