MINOR: listener: do not restrict CLI to first group anymore

Now that we're able to run listeners on any set of groups, we don't need
to maintain a special case about the stats socket anymore. It used to be
forced to group 1 only so as to avoid startup failures in case several
groups were configured, but if it's done now, it will automatically bind
the needed FDs to have one per group so this is no more an issue.
1 file changed