Add error check for writing RDB checksum
Add error check for writing RDB checksum

Closes #857

MSOpenTech/redis,xuzhezhaozhao/redis_reading,ttuna/msot-redis,himoca/redis,splitice/redis,MSOpenTech/redis,jxwr/redis,spearhead-ea/redis,splitice/redis,HunanTV/redis,darksideofthemoo/redis-histogram,ksarch-saas/redis,ttuna/msot-redis,spearhead-ea/redis,maodeyi/redis_lua,HunanTV/redis,maodeyi/redis_lua,HunanTV/redis,ttuna/msot-redis,ksarch-saas/redis,slfs007/mk-redis,himoca/redis,MSOpenTech/redis,darksideofthemoo/redis-histogram,maodeyi/redis_lua,splitice/redis,xuzhezhaozhao/redis_reading,ttuna/msot-redis,ttuna/msot-redis,louisliangjun/redis,louisliangjun/redis,jxwr/redis,splitice/redis,slfs007/mk-redis,louisliangjun/redis,MSOpenTech/redis,ramonsnir/redis,xuzhezhaozhao/redis_reading,darksideofthemoo/redis-histogram,ksarch-saas/redis,himoca/redis,ramonsnir/redis,spearhead-ea/redis,louisliangjun/redis,ksarch-saas/redis,ramonsnir/redis,HunanTV/redis,xuzhezhaozhao/redis_reading,MSOpenTech/redis,slfs007/mk-redis,darksideofthemoo/redis-histogram,jxwr/redis