New test for another error case in DepositScriptAddress

> Line 411 in pool.go is not a return statement:

Sorry, you might have seen this before I changed that to say "insert". If you return nil, nil, basically, your test passes when it's looking for this function to fail.

> What I meant about testName is that it's useful when you have
> table-driven tests, but redundant otherwise.

Just looked through manager_test.go. There's never a time when testName is an empty string. If you're going to use their function, you should use it the way they use it.