Force compile needed after adding `configparser_ex`

[axelson]

If you have a running project and you:

• stop your server
• add configparser_ex to your mix.exs
• run mix deps.get
• start your server
• call ExAws.CredentialsIni.File.security_credentials(nil, nil) then ConfigParser required to use is raised

Instead I'd expect the ExAws.CredentialsIni.File to be recompiled.

I think this happens because ExAws.CredentialsIni.File is still defined even if ConfigParser is not available.