Option Name:authenticate_cache_garbage_interval
Replaces:
Requires:--enable-auth
Default Value:authenticate_cache_garbage_interval 1 hour
Suggested Config:

	The time period between garbage collection across the username cache.
	This is a trade-off between memory utilization (long intervals - say
	2 days) and CPU (short intervals - say 1 minute). Only change if you
	have good reason to.