Update tests after moving services

Author: gcatanese

spec/client_spec.rb

@@ -25,10 +25,10 @@
   end
 
   it 'fails payments call without WS user and password' do
-    expect { @shared_values[:client].payment.authorise('{}') }
+    expect { @shared_values[:client].payment.payments_api.authorise('{}') }
       .to raise_error(Adyen::AuthenticationError)
     @shared_values[:client].ws_user = @shared_values[:ws_user]
-    expect { @shared_values[:client].payment.authorise('{}') }
+    expect { @shared_values[:client].payment.payments_api.authorise('{}') }
       .to raise_error(Adyen::AuthenticationError)
   end