redis-cli --bigkeys / memkeys, report detailed error on dbsize failure (#8740)
redis-cli --bigkeys / memkeys, report detailed error on dbsize failure (#8740)

When DBSIZE failed (e.g. on AUTH error), the printed error didn't reflect the reason.
ofirluzon/redis,yossigo/redis,PKRoma/redis,ofirluzon/redis,oranagra/redis,soloestoy/redis,ofirluzon/redis,charsyam/redis,antirez/redis,soloestoy/redis,yossigo/redis,PKRoma/redis,ofirluzon/redis,charsyam/redis,soloestoy/redis,antirez/redis,ctripcorp/redis,yossigo/redis,soloestoy/redis,neomantra/redis,yossigo/redis,ofirluzon/redis,antirez/redis,neomantra/redis,charsyam/redis,ctripcorp/redis,charsyam/redis,PKRoma/redis,PKRoma/redis,neomantra/redis,oranagra/redis,ctripcorp/redis,soloestoy/redis,PKRoma/redis,oranagra/redis,ctripcorp/redis,neomantra/redis,antirez/redis,charsyam/redis,oranagra/redis,neomantra/redis,yossigo/redis,oranagra/redis