Assertion failure in VCL_DelBackend()

[Dridi Boukelmoune]

> You guys are seriously missing my point here.
>
> The point is that we should make it simple and safe for a VMOD
> to say:
>
>         Here is a director, please destroy it when...
>         [  ]    This transaction is over
>         [  ]    This VCL becomes cold
>         [  ]    (Any other which might make sense)
>         [  ]    I'l take care of it myself
>
> And the reasone we should make it easy is *EXACTLY* to not hav
> dangling pointers etc.

You are right, I did miss most of this point. I did get the feel of
having different scopes with the different kinds of PRIV pointers, but
not to this extent.

In this case I might have to revisit the docs since I initially wrote
them with the VCL's lifespan in mind in the "I'll take care of it
myself" case before the 4.1 release.