Fix VS 10 value of CMAKE_CFG_INTDIR

VS 10 provides $(Configuration) and $(ConfigurationName) but only the
former is documented so we prefer it.  This also makes CMAKE_CFG_INTDIR
consistent with its documentation.  See issue #9916.

Source/cmGlobalVisualStudio10Generator.h

@@ -67,7 +67,7 @@ public:
    */
   virtual std::string GetUserMacrosRegKeyBase();
   virtual const char* GetCMakeCFGInitDirectory() 
-    { return "$(ConfigurationName)";} 
+    { return "$(Configuration)";}
 protected:
   virtual const char* GetIDEVersion() { return "10.0"; }
 };