Insert filter from DLL does not persist when graph is saved and reloaded as XML file

[mikecopperwhite]

Steps to reproduce:
1: Graph/Insert FIlter From DLL.. using DLL which is the NOT the registered COM server DLL for that filter
1a: right click on the filter select Properties.../Filter tab/File/File Path shows the DLL chosen in step 1, not the registered DLL
2: Save file as GRFX XML file (not GRF file)
2a: File Path is still correct as step 1a:
3: Reload the graph from the GRFX XML file saved in step 2
4: get the File Path by steps in 1a:

EXPECTED:
File path in step 4 is the DLL selected in step 1:

ACTUAL:
File Path in step 4 is the registered COM server DLL

NB saving and loading as a GRF file never persists inserting filter from DLL. The registered COM server DLL is always used.

[mikecopperwhite]

Fixed by making sure created_from_dll flag set when GRFX XML file contains class_factory_dll tag.