[frontend/contest] Fixing constest plugin with new database date format

+ course_factory method used on taskset_factory

inginious/frontend/plugins/contests/__init__.py

@@ -83,8 +83,8 @@ def course_menu(course, template_helper):
 
     contest_data = task_dispenser.get_contest_data()
     if contest_data['enabled']:
-        start = datetime.strptime(contest_data['start'], "%Y-%m-%d %H:%M:%S")
-        end = datetime.strptime(contest_data['end'], "%Y-%m-%d %H:%M:%S")
+        start = contest_data['start']
+        end = contest_data['end']
         blackout = end - timedelta(hours=contest_data['blackout'])
         return template_helper.render("course_menu.html", template_folder="frontend/plugins/contests",
                                       course=course, start=start, end=end, blackout=blackout)
@@ -96,15 +96,15 @@ class ContestScoreboard(INGIniousAuthPage):
     """ Displays the scoreboard of the contest """
 
     def GET_AUTH(self, courseid):  # pylint: disable=arguments-differ
-        course = self.taskset_factory.get_course(courseid)
+        course = self.course_factory.get_course(courseid)
         task_dispenser = course.get_task_dispenser()
         if not task_dispenser.get_id() == Contest.get_id():
             raise NotFound()
         contest_data = task_dispenser.get_contest_data()
         if not contest_data['enabled']:
             raise NotFound()
-        start = datetime.strptime(contest_data['start'], "%Y-%m-%d %H:%M:%S")
-        end = datetime.strptime(contest_data['end'], "%Y-%m-%d %H:%M:%S")
+        start = contest_data['start']
+        end = contest_data['end']
         blackout = end - timedelta(hours=contest_data['blackout'])
 
         users = self.user_manager.get_course_registered_users(course)