bug #5418 :  An error is raised from the response of a non sent request!

In order to prevent a possible random bug with  in AngularJS, when an error is received from a remote web service, no error message is rendered to the user if no status code is set in the HTTP response. (At this day, we don't know if the pb comes from a bug in AngularJS or in the way AngularJS is integrated in Silverpeas (that is a frameset-based GUI))