Cluster: remove variable causing warning
Cluster: remove variable causing warning

GCC-4.9 warned about this, but clang didn't.

This commit fixes warning:
sentinel.c: In function 'sentinelReceiveHelloMessages':
sentinel.c:2156:43: warning: variable 'master' set but not used [-Wunused-but-set-variable]
     sentinelRedisInstance *ri = c->data, *master;

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