Fix build, and add a null check

Author: Nicholas King

src/ResourceManager/Websites/Commands.Websites/Cmdlets/BackupRestore/AzureWebAppBackup.cs

@@ -15,7 +15,7 @@ public class AzureWebAppBackup
         public int? BackupId { get; set; }
         public string BackupName { get; set; }
         public string BackupStatus { get; set; }
-        public bool Scheduled { get; set; }
+        public bool? Scheduled { get; set; }
         public long? BackupSizeInBytes { get; set; }
         public long? WebsiteSizeInBytes { get; set; }
         public DateTime? Created { get; set; }

src/ResourceManager/Websites/Commands.Websites/Cmdlets/BackupRestore/BackupRestoreUtils.cs

@@ -16,6 +16,10 @@ public static FrequencyUnit StringToFrequencyUnit(string frequencyUnit)
 
         public static AzureWebAppBackup BackupItemToAppBackup(BackupItem backup, string resourceGroupName, string name, string slot)
         {
+            if (backup == null)
+            {
+                return new AzureWebAppBackup();
+            }
             var dbs = backup.Databases == null ? null : backup.Databases.ToArray();
             string status = backup.Status == null ? null : backup.Status.ToString();
             return new AzureWebAppBackup