virtio: don't try to complete after posting a buffer, if in poll  mode
virtio: don't try to complete after posting a buffer, if in poll  mode

We will poll for it soon anyway, and completing too soon simply reduces
batching.

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