Fixed return value on failure in sort_file

sorter.py

@@ -74,7 +74,7 @@ def sort_file(filename, course=None, lectures=None):
 			handle = '-'.join(splitfilename[:2])
 		courses = query('SELECT * FROM courses WHERE handle = ?', handle)
 		if not courses:
-			return []
+			return [], 0
 		course = courses[0]
 	if not lectures:
 		lectures = query('SELECT * from lectures where course_id = ?', course['id'])