Centos 7.0 execute yum update ——File "/usr/libexec/urlgrabber-ext-down", line 75, in <module> 解决方式

【打开这个文件：/usr/lib/python2.7/site-packages/urlgrabber/grabber.py找到elif errcode in (42, 55,56)   用  elif errcode == 42:替换】