Change std::uint64_t to uint64_t (#354)
Change std::uint64_t to uint64_t (#354)

-This fixes compile errors with default setup on RHEL 6 systems.
xuzhezhaozhao/leveldb,Mojang/leveldb-mcpe,matehat/leveldb,yummyliu/leveldb,google/leveldb,Mojang/leveldb-mcpe,zxylvlp/leveldb,bitcoin-core/leveldb,likema/leveldb,yuwolf/leveldb,cmumford/leveldb,betterdenger/leveldb,jacklicn/leveldb,dwing4g/leveldb,fastogt/leveldb,PFZheng/leveldb,yummyliu/leveldb,PFZheng/leveldb,Mojang/leveldb-mcpe,bitcoin-core/leveldb,dwing4g/leveldb,bitcoin/leveldb,cmumford/leveldb,olzhabay/PMIndexDB,betterdenger/leveldb,norton/leveldb,bitcoin/leveldb,xuerenlv/leveldb,WeiHaocheng/LevelDBBuffer,google/leveldb,fastogt/leveldb,olzhabay/PMIndexDB,matehat/leveldb,fuchsia-mirror/third_party-leveldb,xuerenlv/leveldb,dwing4g/leveldb,betterdenger/leveldb,luke-jr/leveldb,yuwolf/leveldb,Jianbo-Yang/leveldb,yuwolf/leveldb,zxylvlp/leveldb,jacklicn/leveldb,PFZheng/leveldb,matehat/leveldb,xuzhezhaozhao/leveldb,luke-jr/leveldb,olzhabay/PMIndexDB,WeiHaocheng/LevelDBBuffer,fuchsia-mirror/third_party-leveldb,yummyliu/leveldb,bitcoin/leveldb,Jianbo-Yang/leveldb,zxylvlp/leveldb,norton/leveldb,xuerenlv/leveldb,bitcoin-core/leveldb,xuzhezhaozhao/leveldb,norton/leveldb,Jianbo-Yang/leveldb,likema/leveldb,WeiHaocheng/LevelDBBuffer,jacklicn/leveldb