Explicitly retrieving value of DecrementIsNoExcept() as a workaround …

…for a bug in VS2017 where the DecremenIsNoExcept() may return void.

This is possibly related to use of noexcept expresions on destructors.

(Internal change: 2319827)

pxr/base/tf/delegatedCountPtr.h

@@ -202,8 +202,10 @@ class TfDelegatedCountPtr {
     }
 
     /// Call `TfDelegatedCountDecrement` on the held pointer if it is not
-    /// `nullptr`.
-    ~TfDelegatedCountPtr() noexcept(DecrementIsNoExcept()) {
+    /// nullptr`. A bug occurs in VS2017 where calling DecrementIsNoExcept() 
+    /// may return void. The bug is possibly related to an issue with using
+    /// noexcept expressions in destructors.
+    ~TfDelegatedCountPtr() noexcept(DecrementIsNoExcept::value) {
         _DecrementIfValid();
     }