MOBILE-1987 assign: Fix uploading offline files error

Author: crazyserver

www/addons/mod/assign/controllers/edit.js

@@ -98,11 +98,7 @@ angular.module('mm.addons.mod_assign')
                 });
             });
         }).catch(function(message) {
-            if (message) {
-                $mmUtil.showErrorModal(message);
-            } else {
-                $mmUtil.showErrorModal('Error getting assigment data.');
-            }
+            $mmUtil.showErrorModalDefault(message, 'Error getting assigment data.');
             blockData && blockData.back();
             return $q.reject();
         });

www/core/components/fileuploader/services/helper.js

@@ -88,6 +88,10 @@ angular.module('mm.core.fileuploader')
      * @return {Promise}                  Promise resolved when the user confirms or if there's no need to show a modal.
      */
     self.confirmUploadFile = function(size, alwaysConfirm, allowOffline, wifiThreshold, limitedThreshold) {
+        if (size == 0) {
+            return $q.when();
+        }
+
         if (!allowOffline && !$mmApp.isOnline()) {
             return $mmLang.translateAndReject('mm.fileuploader.errormustbeonlinetoupload');
         }