message: WebSites: Add default values to required parameters of BackupSchedule
  WebSites: Add default values to required parameters of BackupSchedule
diff: "frequencyInterval": {
  "format": "int32",
  "description": "How often should be the backup executed (e.g. for weekly backup, this should be set to 7 and FrequencyUnit should be set to Day)",
  + "default": 7,
  "type": "integer"
  },
  "frequencyUnit": {
  - "description": "How often should be the backup executed (e.g. for weekly backup, this should be set to Day and FrequencyInterval should be set to 7)",
  + "description": "The unit of time for how often should be the backup executed (e.g. for weekly backup, this should be set to Day and FrequencyInterval should be set to 7)",
  + "default": "Day",
  "enum": [
  "Day",
  "Hour"
  },
  "keepAtLeastOneBackup": {
  "description": "True if the retention policy should always keep at least one backup in the storage account, regardless how old it is; false otherwise.",
  + "default": true,
  "type": "boolean"
  },
  "retentionPeriodInDays": {
  "format": "int32",
  "description": "After how many days backups should be deleted.",
  + "default": 90,
  "type": "integer"
  },
  "startTime": {
  