Remove 'SecondsOrDuration' for check_interval

Now requires an explicit duration unit. Eg. 30s

config.go

@@ -13,11 +13,11 @@ var errInvalidConfig = errors.New("Invalid configuration")
 
 // Config type is contains all provided user configuration
 type Config struct {
-	CheckInterval     SecondsOrDuration `yaml:"check_interval"`
-	DefaultAlertAfter int16             `yaml:"default_alert_after"`
-	DefaultAlertEvery *int16            `yaml:"default_alert_every"`
-	DefaultAlertDown  []string          `yaml:"default_alert_down"`
-	DefaultAlertUp    []string          `yaml:"default_alert_up"`
+	CheckInterval     time.Duration `yaml:"check_interval"`
+	DefaultAlertAfter int16         `yaml:"default_alert_after"`
+	DefaultAlertEvery *int16        `yaml:"default_alert_every"`
+	DefaultAlertDown  []string      `yaml:"default_alert_down"`
+	DefaultAlertUp    []string      `yaml:"default_alert_up"`
 	Monitors          []*Monitor
 	Alerts            map[string]*Alert
 }
@@ -56,34 +56,6 @@ func (cos *CommandOrShell) UnmarshalYAML(unmarshal func(interface{}) error) erro
 	return nil
 }
 
-// SecondsOrDuration wraps a duration value for parsing a duration or seconds from YAML
-// NOTE: This should be removed in favor of only parsing durations once compatibility is broken
-type SecondsOrDuration struct {
-	value time.Duration
-}
-
-// Value returns a duration value
-func (sod SecondsOrDuration) Value() time.Duration {
-	return sod.value
-}
-
-// UnmarshalYAML allows unmarshalling a duration value or seconds if an int was provided
-func (sod *SecondsOrDuration) UnmarshalYAML(unmarshal func(interface{}) error) error {
-	var seconds int64
-	err := unmarshal(&seconds)
-
-	if err == nil {
-		sod.value = time.Second * time.Duration(seconds)
-
-		return nil
-	}
-
-	// Error indicates that we don't have an int
-	err = unmarshal(&sod.value)
-
-	return err
-}
-
 // IsValid checks config validity and returns true if valid
 func (config Config) IsValid() (isValid bool) {
 	isValid = true