carbon-relay-ng doesn't run on OSX

[fitzoh]

Running on OSX (10.14.2) carbon-relay-ng fails on initialization while attempting to initialize the process reporter.

It's apparently looking for /proc, which does not exist on OSX.

[FATAL] stats: could not initialize process reporter: could not read /proc: stat /proc: no such file or directory

carbon-relay-ng code in question:

carbon-relay-ng/cmd/carbon-relay-ng/carbon-relay-ng.go

Lines 154 to 157 in 76e4304

	_, err = statsmt.NewProcessReporter()
	if err != nil {
	log.Fatalf("stats: could not initialize process reporter: %v", err)
	}

carbon-relay-ng/statsmt/process_reporter.go

Lines 15 to 24 in 76e4304

	func NewProcessReporter() (*ProcessReporter, error) {
	p := ProcessReporter{}
	pid := os.Getpid()
	var err error
	p.proc, err = procfs.NewProc(pid)
	if err != nil {
	return nil, err
	}
	return Register.GetOrAdd("process", &p).(*ProcessReporter), nil
	}