journald unix sockets are leaked whenever Enabled() is called

[jeremy-gill]

The journald logging code appears to leak a unix datagram socket once per call to journal.Enabled() on linux platforms.

An example bit of code follows that leads to an eventual error once the number of open file handles hits the operating system per-process maximum.

package main

import (
	"fmt"

	"github.com/rs/zerolog"
	"github.com/rs/zerolog/journald"
	"github.com/rs/zerolog/log"
)

func main() {

	var (
		i int
	)

	writers := journald.NewJournalDWriter()
	log.Logger = log.Output(writers)

	for {
		log.WithLevel(zerolog.InfoLevel).Msg(fmt.Sprintf("Hello world %d", i))
		i++
	}
}