Fix usage of data in Field.get_data

Field.get_data returns directly the data.

src/view/form.js

@@ -2827,7 +2827,7 @@
             var field = this.field();
             var record = this.record();
             field.get_data(record).done(function(data) {
-                var blob = new Blob([data[0].binary],
+                var blob = new Blob([data],
                         {type: 'application/octet-binary'});
                 var blob_url = window.URL.createObjectURL(blob);
                 if (this.blob_url) {