catch ValueError in reapply_extensions command

Raised when the course name is not of form ORG/COURSE/NAME

lms/djangoapps/instructor/management/commands/reapply_extensions.py

@@ -16,5 +16,5 @@ class Command(BaseCommand):
         try:
             course = get_course_by_id(args[0])
             fix_missing_extensions(course)
-        except Http404 as e:
+        except (ValueError, Http404) as e:
             raise CommandError(e)