fix code

Author: WiFeng

metrics/prometheus/prometheus.go

@@ -1,8 +1,6 @@
 package prometheus
 
-import (
-	"github.com/WiFeng/go-sky/config"
-)
+import "github.com/WiFeng/go-sky/config"
 
 var (
 	DefaultBuckets    = []float64{.005, .01, .025, .05, .1, .25, .5, 1, 2.5, 5, 10}