Open Stack

Hi,

I see that the stack delete method is too long to comprehend easily
without going to-and-fro few times. I think we should refactor it and
move out the "UpdateReplace" related logic for backup stack to another
method. We can also move the user credentials deletion related logic to
another method. With this we will can have more testable (each method
can be tested independently) and lucid code.

Don't know if someone has already taken it. I am sure the refactor will
be helpful.

- Anant