misc
Rename {quiz_pool_user_answers}.question_nid to {quiz_pool_user_answers}.question_qid
Rename {quiz_pool_user_answers_questions}.question_nid to {quiz_pool_user_answers_questions}.question_qid
Rename {quiz_pool_user_answers_questions}.pool_nid to {quiz_pool_user_answers_questions}.pool_qid