module_invoke_all should be invoked before cancel

I have encountered, while extending the module, that on cancel of a signup module_invoke_all is called after deletion of the data on the db, I presume that I am not the only one that references this data in other parts (I particularly use part of the form_data) so I propose the module_invoke_all call to be made before deletion of the data, this could even be useful if someone wants to do checkings before allow the cancel.
I provide a patch of my version that demonstrates the solution, please excuse the lack of adaptation to generic code it just came out from my svn diff when committing and I remembered to file the report.