Merge pull request #9584 from keveleigh/openxr-2020

Wrap namespace in #if MSFT_OPENXR_0_2_0_OR_NEWER

Author: David Kline

Assets/MRTK/Providers/OpenXR/Scripts/OpenXRHandMeshProvider.cs

@@ -1,7 +1,10 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
+#if MSFT_OPENXR_0_2_0_OR_NEWER
 using Microsoft.MixedReality.OpenXR;
+#endif // MSFT_OPENXR_0_2_0_OR_NEWER
+
 using Microsoft.MixedReality.Toolkit.Input;
 using System.Collections.Generic;
 using UnityEngine;