Fix Register

libraries/metrics/metrics.coffee

@@ -1,4 +1,5 @@
 prom = require('prom-client')
+Register = require('prom-client').register
 
 collectDefaultMetrics = prom.collectDefaultMetrics
 
@@ -15,7 +16,7 @@ destructors = []
 require "./uv_threadpool_size"
 
 module.exports = Metrics =
-	register: require('prom-client').register
+	register:Register
 	initialize: (_name) ->
 		appname = _name
 		collectDefaultMetrics({ timeout: 5000, prefix: Metrics.buildPromKey()})