使用结巴分词，会输出如下日志：
Building prefix dict from /usr/lib/python2.7/site-packages/jieba/dict.txt ... Loading model from cache /tmp/jieba.cache Loading model cost 0.182227134705 seconds. Prefix dict has been built succesfully.
logging日志级别（5个等级），从低到高分别是：
DEBUG INFO WARNING ERROR CRITICAL
不显示debug信息，只要大于 logging.DEBUG 级别即可，比如：
import logging jieba.setLogLevel(logging.INFO)
参考：
jieba如何关闭stderr的日志 #255
