Fixed bug in parsing of urandom struct so that seed

is set to an integer (and correctly saved) instead of a tuple.

common/lib/capa/capa/capa_problem.py

@@ -118,7 +118,7 @@ class LoncapaProblem(object):
         #       3. Assign from the OS's random number generator
         self.seed = state.get('seed', seed)
         if self.seed is None:
-            self.seed = struct.unpack('i', os.urandom(4))
+            self.seed = struct.unpack('i', os.urandom(4))[0]
         self.student_answers = state.get('student_answers', {})
         if 'correct_map' in state:
             self.correct_map.set_dict(state['correct_map'])