controller: add barrier request after l3 termination add/del
controller: add barrier request after l3 termination add/del

When updating the layer 3 termination entries, its necessary to process
the deletion one first and then the addition. Barrier requests ensure this
behaviour

Signed-off-by: Rubens Figueiredo <22177f75c46bd149db738f8a1dfeab4c8cbd2d82@bisdn.de>

bisdn/basebox,bisdn/basebox,bisdn/basebox,bisdn/basebox