Streams: fix XREAD missing check for NULL object.
Streams: fix XREAD missing check for NULL object.

GitHubMota/redis,yossigo/redis,pmem/redis,soveran/redis,oranagra/redis,soloestoy/redis,charsyam/redis,ofirluzon/redis,neomantra/redis,pmem/redis,soveran/redis,soveran/redis,nnog/redis,yossigo/redis,neomantra/redis,GitHubMota/redis,ctripcorp/redis,antirez/redis,soloestoy/redis,oranagra/redis,spinlock/redis,yossigo/redis,ctripcorp/redis,spinlock/redis,ofirluzon/redis,pmem/redis,spinlock/redis,soveran/redis,antirez/redis,PKRoma/redis,nnog/redis,charsyam/redis,spinlock/redis,soloestoy/redis,oranagra/redis,GitHubMota/redis,charsyam/redis,neomantra/redis,ofirluzon/redis,charsyam/redis,neomantra/redis,PKRoma/redis,pmem/redis,antirez/redis,ctripcorp/redis,nnog/redis,GitHubMota/redis,oranagra/redis,neomantra/redis,charsyam/redis,yossigo/redis,oranagra/redis,antirez/redis,PKRoma/redis,ofirluzon/redis,ofirluzon/redis,soloestoy/redis,ctripcorp/redis,yossigo/redis,PKRoma/redis,nnog/redis,soloestoy/redis,PKRoma/redis