panic: duplicate metrics collector registration attempted

goroutine 212 [running]:
github.com/grafana/loki/vendor/github.com/prometheus/client_golang/prometheus.(*Registry).MustRegister(0xc0000de370, 0xc000670090, 0x1, 0x1)
	/deploy/go/src/github.com/grafana/loki/vendor/github.com/prometheus/client_golang/prometheus/registry.go:391 +0xad
github.com/grafana/loki/vendor/github.com/prometheus/client_golang/prometheus.MustRegister(...)
	/deploy/go/src/github.com/grafana/loki/vendor/github.com/prometheus/client_golang/prometheus/registry.go:176
github.com/grafana/loki/vendor/github.com/weaveworks/common/server.New(0x0, 0x0, 0x0, 0x0, 0x2378, 0x0, 0x0, 0x0, 0x0, 0x0, ...)
	/deploy/go/src/github.com/grafana/loki/vendor/github.com/weaveworks/common/server/server.go:111 +0x464
github.com/grafana/loki/pkg/promtail/server.New(0x0, 0x0, 0x0, 0x0, 0x2378, 0x0, 0x0, 0x0, 0x0, 0x0, ...)
	/deploy/go/src/github.com/grafana/loki/pkg/promtail/server/server.go:36 +0x55
github.com/grafana/loki/pkg/promtail.New(0x7fff0d6b2248, 0xf, 0x6, 0x0, 0x0)
	/deploy/go/src/github.com/grafana/loki/pkg/promtail/promtail.go:52 +0x319
main.(*Master).DoReload(0xc00002a420, 0x0, 0x0)
	/deploy/go/src/github.com/grafana/loki/cmd/promtail/main.go:48 +0x74
main.(*Master).Reload.func1(0xc00002a420)
	/deploy/go/src/github.com/grafana/loki/cmd/promtail/main.go:40 +0x2b
created by main.(*Master).Reload
	/deploy/go/src/github.com/grafana/loki/cmd/promtail/main.go:39 +0x3f