v2/checksum: fix crc32-c case
v2/checksum: fix crc32-c case

chenwenbin928/tchannel,RyanTech/tchannel,savaki/tchannel,vanloswang/tchannel,Zirpon/tchannel,hustxiaoc/tchannel,sasa233/tchannel,bunnyblue/tchannel,i/tchannel,chenwenbin928/tchannel,hustxiaoc/tchannel,savaki/tchannel,bunnyblue/tchannel,savaki/tchannel,sasa233/tchannel,RyanTech/tchannel,vanloswang/tchannel,benfleis/tchannel,vanloswang/tchannel,chenwenbin928/tchannel,Zirpon/tchannel,hustxiaoc/tchannel,benfleis/tchannel,i/tchannel,Zirpon/tchannel,i/tchannel,bunnyblue/tchannel,RyanTech/tchannel,sasa233/tchannel,benfleis/tchannel