xen: request tx notification on tx completion
xen: request tx notification on tx completion

Otherwise, we never learn that transmission has completed and never
recycle ring entries.

This is still a little lame as we don't do any batching.

bowlofstew/scylla,ducthangho/imdb,flashbuckets/seastar,scylladb/scylla-seastar,anzihenry/seastar,justintung/scylla,glommer/scylla,dwdm/scylla,scylladb/scylla-seastar,xtao/seastar,shaunstanislaus/scylla,rluta/scylla,dreamsxin/seastar,stamhe/seastar,scylladb/scylla,tempbottle/scylla,mixja/seastar,bzero/seastar,respu/scylla,joerg84/seastar,norcimo5/seastar,wildinto/scylla,raphaelsc/seastar,wildinto/seastar,hongliangzhao/seastar,shyamalschandra/seastar,kjniemi/scylla,dreamsxin/seastar,avikivity/seastar,chunshengster/seastar,stamhe/seastar,guiquanz/scylla,linearregression/scylla,phonkee/scylla,leejir/seastar,rentongzhang/scylla,shaunstanislaus/scylla,scylladb/scylla,glommer/scylla,koolhazz/seastar,jonathanleang/seastar,mixja/seastar,eklitzke/scylla,kangkot/scylla,syuu1228/seastar,chunshengster/seastar,stamhe/scylla,linearregression/seastar,printedheart/seastar,dwdm/seastar,kangkot/scylla,flashbuckets/seastar,bowlofstew/scylla,raphaelsc/scylla,respu/scylla,joerg84/seastar,scylladb/scylla,gwicke/scylla,raphaelsc/seastar,flashbuckets/seastar,kjniemi/seastar,scylladb/seastar,ducthangho/imdb,tempbottle/scylla,stamhe/seastar,rentongzhang/scylla,aruanruan/scylla,xtao/seastar,sjperkins/seastar,avikivity/scylla,phonkee/scylla,cloudius-systems/seastar,avikivity/scylla,eklitzke/scylla,slivne/seastar,respu/scylla,acbellini/seastar,guiquanz/scylla,capturePointer/scylla,avikivity/scylla,linearregression/seastar,wildinto/scylla,linearregression/scylla,dwdm/scylla,dreamsxin/seastar,hongliangzhao/seastar,scylladb/scylla-seastar,acbellini/seastar,wildinto/seastar,chunshengster/seastar,senseb/scylla,scylladb/seastar,capturePointer/scylla,cloudius-systems/seastar,slivne/seastar,acbellini/scylla,leejir/seastar,raphaelsc/scylla,duarten/scylla,leejir/seastar,bowlofstew/seastar,guiquanz/scylla,koolhazz/seastar,shyamalschandra/seastar,tempbottle/seastar,bowlofstew/seastar,asias/scylla,kangkot/scylla,raphaelsc/seastar,tempbottle/scylla,mixja/seastar,linearregression/seastar,duarten/scylla,scylladb/scylla,bowlofstew/seastar,printedheart/seastar,duarten/scylla,victorbriz/scylla,stamhe/scylla,dwdm/seastar,shaunstanislaus/scylla,sjperkins/seastar,tempbottle/seastar,acbellini/scylla,rluta/scylla,aruanruan/scylla,linearregression/scylla,senseb/scylla,jonathanleang/seastar,xtao/seastar,rentongzhang/scylla,justintung/scylla,victorbriz/scylla,syuu1228/seastar,ducthangho/imdb,eklitzke/scylla,glommer/scylla,sjperkins/seastar,norcimo5/seastar,dwdm/seastar,kjniemi/seastar,bowlofstew/scylla,avikivity/seastar,shyamalschandra/seastar,gwicke/scylla,jonathanleang/seastar,printedheart/seastar,scylladb/seastar,asias/scylla,koolhazz/seastar,kjniemi/seastar,acbellini/scylla,hongliangzhao/seastar,raphaelsc/scylla,phonkee/scylla,cloudius-systems/seastar,justintung/scylla,bzero/seastar,dwdm/scylla,syuu1228/seastar,victorbriz/scylla,joerg84/seastar,acbellini/seastar,tempbottle/seastar,bzero/seastar,aruanruan/scylla,slivne/seastar,senseb/scylla,wildinto/scylla,gwicke/scylla,avikivity/seastar,kjniemi/scylla,norcimo5/seastar,kjniemi/scylla,rluta/scylla,asias/scylla,stamhe/scylla,anzihenry/seastar,anzihenry/seastar,capturePointer/scylla,wildinto/seastar