write_file() called when changing Activity name

[Urko Fernandez]

Is there a way to know whether the write_file() method is called while
changing the name of the activity or when closing the activity? 
I want to delete a file created in the instance folder after closing the
activity. I know files in the instance folder are to be deleted
automatically, but on sugar-jhbuild they stay (in QEMU the file is
deleted when placed in $SUGAR_ACTIVITY_ROOT/instance/ correctly)

Regards, 

Urko