middleware/erratic: add delaying queries (#614)

* middleware/erratic: add delying queries

* Dont println

middleware/erratic/erratic_test.go

@@ -11,7 +11,7 @@ import (
 )
 
 func TestErraticDrop(t *testing.T) {
-	e := &Erratic{amount: 2} // 50% drops
+	e := &Erratic{drop: 2} // 50% drops
 
 	tests := []struct {
 		expectedCode int