__kfree_skb eventually calls kfree_skb violating dropwatch assumption

kfree_skb can be called from __kfree_skb through the following call chain :

kfree_skb  <- skb_drop_list <- skb_drop_fraglist <- skb_release_data <-  skb_release_all <- __kfree_skb (on the 2.38.4 kernel).

This violates the assumption in the dropwatch tool that discarded packets go through the kfree_skb path and all others must go through the consume_skb path (thus resulting in the over-counting of discarded packets in dropwatch).

Neil Horman the author of dropwatch suggested that this could be fixed by skb_drop_list calling consume_skb instead of kfree_skb.

Charles