r15824: fixed a subtle talloc bug to do with memory context loops. When you

r15824: fixed a subtle talloc bug to do with memory context loops. When you
have a structure that references one of its parents, and a parent of
that parent is freed, then the whole structure should be freed, not
just the reference.

this was found by the change notify code, as a side effect of fixing
the memory leak yesterday
(This used to be commit 70531dcaeeb9314d410baa0d285df6a265311541)