DataDisk should be null if there are no additional images.

Author: sergey-shandar

src/ResourceManager/Compute/Commands.Compute/Strategies/ComputeRp/DataDiskStrategy.cs

@@ -13,19 +13,21 @@ static IList<T> CreateDataDisks<T>(
             IEnumerable<int> dataDiskSizes,
             Func<DiskCreateOptionTypes, int, int?, T> createDataDisk)
         {
+            if (dataDiskSizes == null)
+            {
+                return null;
+            }
             imageDataDiskLuns = imageDataDiskLuns.EmptyIfNull();
             var firstLun = imageDataDiskLuns
                 .Select(v => v + 1)
                 .Concat(new[] { 0 })
                 .Max();
             return imageDataDiskLuns
                 .Select(lun => createDataDisk(DiskCreateOptionTypes.FromImage, lun, null))
-                .Concat(dataDiskSizes
-                    .EmptyIfNull()
-                    .Select((size, i) => createDataDisk(
-                        DiskCreateOptionTypes.Empty,
-                        i + firstLun,
-                        size)))
+                .Concat(dataDiskSizes.Select((size, i) => createDataDisk(
+                    DiskCreateOptionTypes.Empty,
+                    i + firstLun,
+                    size)))
                 .ToList();
         }