Fix segfault;fix config problem

[haorenfsa]

fix segfault when running out memory;
fix limit_traffic_rate no effect when set in http/server block

[haorenfsa]

this patch aims to fix issue #11 #8 . For work reason, I'll be using and optimizing this module in my fork repo in following couple of month. Hope this can help you.

[superkuh]

Thanks for this submitting this patch, haorenfsa. It seems to have solved my problem.

[haorenfsa]

@superkuh
Glad that helped : - )