task webflow does not handle history well for executable subflow.

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Go to /get/task select a tasks w/ remote executable 
2. Select and upload an executable, go through the wizard to the end, save it
3. In the success page, click "back" of the browse, this brings you back to
the save page, if you save again, you will get an exception.

Reason:
The initial saving sends the executable bundle over to content repository.
This is the side-effect of the webflow.  When exit from he subflow, the
browser "back" triggers spring webflow to restore most of things except
this side-effect, which leads this error.  

spring view-state transition can disable the back with history attribute. 
But the subflow transition does not support it. 

Original issue reported on code.google.com by zgg...@gmail.com on 1 Jun 2010 at 6:47

[GoogleCodeExporter]

This is a relative rare use-case.  save-back-save again.  

Original comment by zgg...@gmail.com on 1 Jun 2010 at 6:49