Cluster: Fix segfault if cluster config corrupt
Cluster: Fix segfault if cluster config corrupt

This commit adds a size check after initial config
line parsing to make sure we have *at least* 8 arguments
per line.

Also, instead of asserting for cluster->myself, we just test
and error out normally (since the error does a hard exit anyway).

Closes #1597

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