Cluster: initialize mf_end.
Cluster: initialize mf_end.

Can't be initialized by resetManualFailover() since it's actual state
the function uses, so we need to initialize it at startup time. Not
really a bug in practical terms, but showed up into valgrind and is not
technically correct anyway.

JackieXie168/redis,JackieXie168/redis,JackieXie168/redis,JackieXie168/redis