Endless notary deposits

[carpawell]

Context

We experience fallback transaction is valid after the deposit is unlocked: ValidUntilBlock is 8900, deposit lock expires at 8058 errors sometimes. Their nature is not fully understood but the fact is that we lost some deposits.

Suggestion

Try to use the biggest till always (e.g. max int64).

Pitfalls of this question:

1. I do not remember if it is allowed to make the same notary deposits (the same till, the same amount).
2. Doing a deposit with max int64 forces us to use the same till in all the further deposits (it is impossible to make deposits with newTill < currentTill).
3. We have the same deposit logic in the side and main chains. While it is kinda ok to block some GAS forever in the sidechain, doing that in the main chain may have some misunderstanding (if we ever have notary turned on in the main chain).

Also

1. New logs on notary deposits (with the amount, till, and epoch) could be useful for debugging.