Bug#879518: ifupdown: fail to start with bridge_stp on and recursion detected in parent-lock with vlan after jessie upgrade

[Daniel Huhardeaux]

I investigate further and discover that the the message "recursion 
detected in parent-lock" appears in *ALL* vlan interfaces (.1 .2 .100 
.1001 .1002), not only the 2 first one as I reported.
After having removed all pre-up bone and pre-up bone.vlan in interfaces 
file, I was able to again set bridge_stp on without getting the "set 
forward delay failed: Numerical result out of range" message.
This means that bridge_stp on error is a result from the pre-up bone and 
bone.vlan behavior.

Regards
--
Daniel