getImage函数中将找到的img['src']改为img['pagespeed_lazy_src'] 因为在gae上，获取到的网页没有src属性，是经过加速的pagespeed_lazy_src属性
修复image_fetch ['src']改为 ['pagespeed_lazy_src']
Merge pull request #4 from cadl/fix-image_fetch

Fix image fetch试一试