Close popup instead of displaying an error when user clicks cancel on the Google token popup

Steps to reproduce:

1. In Home > OAuth token, click Add a new googledrive token.
2. In the popup click Cancel.
   The popup shows the text below:

   {"entity-type":"exception","code":"javax.ws.rs.WebApplicationException","status":500,"message":"com.sun.jersey.api.MessageException: A message body writer for Java class org.nuxeo.ecm.webengine.model.exceptions.WebDocumentException, and Java type class org.nuxeo.ecm.webengine.model.exceptions.WebDocumentException, and MIME media type text/html; charset=UTF-8 was not found.\n"}