Cluster: fixed data_age computation / check integer overflow.
Cluster: fixed data_age computation / check integer overflow.

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