Undoing a DeleteOperationCommand_Aai20 does not restore the operation's message

[DyspC]

From what I've seen in debug mode the message is not saved in the command so the field is probably missing from the result of DataModelWriter

Here is a failing test suite deleteoperationwithmessage.zip

[EricWittmann]

@carlesarnal Can you take a look at this? I was thinking it might be good to get you looking at the data models repo a bit. Let me know if you want a quick primer and we can schedule something.

[carlesarnal]

Hey, sure. I'll take a look and let you know if I need help/guidance.

[carlesarnal]

Sorry for the delay, I have added a pull request in an attempt to resolve this issue.