net: unfuturize packet fragmentation
net: unfuturize packet fragmentation

Since sending of a single packet does not involve futures anymore we can
simplify this code.

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