gauge.go
func (m *CirconusMetrics) RemoveGauge(metric string) {
	m.gm.Lock()
	defer m.gm.Unlock()
	delete(m.gauges, metric)
}
func (m *CirconusMetrics) RemoveGauge(metric string) {
	m.gm.Lock()
	defer m.gm.Unlock()
	delete(m.gauges, metric)
}
// RemoveGauge removes a gauge