BUG/MINOR: Fix option redispatch serialization

When the redispatch interval is set to zero, remove
the option from the configuration.

Author: oliwer

configuration/backend_test.go

@@ -825,6 +825,10 @@ func TestCreateEditDeleteBackend(t *testing.T) {
 			{Name: "test_errors_all"},
 		},
 		Disabled: true,
+		Redispatch: &models.Redispatch{
+			Enabled:  misc.StringP("enabled"),
+			Interval: 0,
+		},
 	}
 
 	err := clientTest.CreateBackend(b, "", version)
@@ -839,6 +843,9 @@ func TestCreateEditDeleteBackend(t *testing.T) {
 		t.Error(err.Error())
 	}
 
+	// A redispatch with a zero interval is automatically removed from configuration.
+	b.Redispatch = nil
+
 	var givenJSONB []byte
 	givenJSONB, err = b.MarshalBinary()
 	if err != nil {

configuration/configuration.go

@@ -2443,6 +2443,9 @@ func (s *SectionObject) redispatch(field reflect.Value) error {
 		if *br.Enabled == "disabled" {
 			d.NoOption = true
 		}
+		if br.Interval == 0 {
+			d = nil
+		}
 		if err := s.set("option redispatch", d); err != nil {
 			return err
 		}