IOException rescue is too broad #12

At https://github.com/twingly/ecco/blob/v0.5.0/lib/ecco/client.rb#L49 we rescue IOException, and always return Ecco::Error::ConnectionError, but we could improve that and return different errors for different situations.

mysql-binlog-connector-java has AuthenticationException that inherits from ServerException that inherits IOException.

At https://github.com/twingly/ecco/blob/v0.5.0/spec/integration/client_spec.rb#L273 we could expect the authentication error I think.