Change option signature to not return error

What does this MR do?

Change the option signature to not return an error

• Current option to set max age always returns a nil error.
• While I was here, I took the opportunity to refactor the client tests.
• The existing tests did not test all the error cases.

Why was this MR needed?

To improve the code quality and testing.

What's the best way to test this MR?

go test -race ./network/...