[mdl] fix crash on shutdown of neuray by resetting everything.

Change-Id: I51ce3ef0ca1e4cb13e1f2bad7b76968609d25629
Reviewed-on: http://git-master/r/1259939
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Markus Tavenrath <[email protected]>
Tested-by: Markus Tavenrath <[email protected]>

Author: asuessenbach

dp/fx/mdl/src/MDLTokenizer.cpp

@@ -246,12 +246,15 @@ namespace dp
 
       MDLTokenizer::~MDLTokenizer()
       {
-        m_database.reset();
+        // throw away everything before m_neuray is shut down
         m_mdlValueFactory.reset();
         m_mdlExpressionFactory.reset();
         m_mdlFactory.reset();
-        m_mdlCompiler.reset();    // throw away before m_neuray is shut down
-        m_neuray->shutdown();
+        m_transaction->commit();
+        m_transaction.reset();
+        m_mdlCompiler.reset();
+        m_database.reset();
+        DP_VERIFY(m_neuray->shutdown() == 0);
       }
 
       bool MDLTokenizer::checkDefaultField(std::string const& fieldName, mi::base::Handle<mi::neuraylib::IExpression const> const& expression)