Adding set elements

[Thomas Köller <thomas@xxxxxxxxxxxxxxxxxx>]

What exactly happens if an attempt is made to add another element to a 
set that is already full? I ran into this condition and found that a 
subsequent 'nft list ruleset' would display the set with no contained 
elements at all.

I think that a reasonable way to handle this case would be to apply sume 
LRU strategy to free up a slot, but that is apparently not the case?

Thomas