rpc: handle exception during unmarshalling
rpc: handle exception during unmarshalling

Unmarshalling function should not throw, but in case it does move
connection to an error state and report the error to an rpc client.
Currently all errors are reported as rpc::closed_error().

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