clean_up

# File ext/dl/win32/lib/win32/sspi.rb, line 304
                        def clean_up
                                # free structures allocated
                                @cleaned_up = true
                                API::FreeCredentialsHandle.call(@credentials.to_p)
                                API::DeleteSecurityContext.call(@context.to_p)
                                @context = nil
                                @credentials = nil
                                @contextAttributes = nil
                        end