[Cake] Possible BUG - parent backlog incorrectly updated in case of NET_XMIT_CN

[Jonathan Morton]

> On 7 Jun, 2016, at 14:20, Kevin Darbyshire-Bryant <kevin at darbyshire-bryant.me.uk> wrote:
> 
> I had a nose at CAKE but couldn't quit work out if a similar issue is present but I suspect it is. Certainly if Eric can't get it right "My prior attempt to fix the backlogs of parents failed." then it's not an 'obvious to solve' problem :-)

It appears my code already handles it correctly.  This is most likely because it inherited the analogous handling from the old function called here.

 - Jonathan Morton