transport/server: Fix response::write_byte()
transport/server: Fix response::write_byte()

The last two arguments to vector::insert() are flipped which causes us
to fill the vector with 'b' bytes of value 0x01. Switch to the single
element insertion variant to fix the issue.

Spotted by dtest push notification tests.

Signed-off-by: Pekka Enberg <add4fcd06328a394f0ad91feda7ee057316dc5ed@cloudius-systems.com>

scylladb/scylla,rluta/scylla,guiquanz/scylla,acbellini/scylla,respu/scylla,victorbriz/scylla,justintung/scylla,kjniemi/scylla,respu/scylla,justintung/scylla,linearregression/scylla,stamhe/scylla,asias/scylla,linearregression/scylla,kangkot/scylla,duarten/scylla,gwicke/scylla,wildinto/scylla,tempbottle/scylla,wildinto/scylla,gwicke/scylla,asias/scylla,linearregression/scylla,duarten/scylla,rentongzhang/scylla,eklitzke/scylla,rentongzhang/scylla,aruanruan/scylla,kjniemi/scylla,shaunstanislaus/scylla,glommer/scylla,senseb/scylla,rluta/scylla,raphaelsc/scylla,avikivity/scylla,acbellini/scylla,tempbottle/scylla,capturePointer/scylla,bowlofstew/scylla,victorbriz/scylla,scylladb/scylla,avikivity/scylla,capturePointer/scylla,stamhe/scylla,victorbriz/scylla,glommer/scylla,dwdm/scylla,stamhe/scylla,phonkee/scylla,shaunstanislaus/scylla,bowlofstew/scylla,phonkee/scylla,glommer/scylla,kangkot/scylla,eklitzke/scylla,gwicke/scylla,phonkee/scylla,asias/scylla,justintung/scylla,bowlofstew/scylla,raphaelsc/scylla,kjniemi/scylla,kangkot/scylla,wildinto/scylla,dwdm/scylla,tempbottle/scylla,aruanruan/scylla,rentongzhang/scylla,dwdm/scylla,raphaelsc/scylla,rluta/scylla,guiquanz/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla,senseb/scylla,eklitzke/scylla,acbellini/scylla,capturePointer/scylla,senseb/scylla,guiquanz/scylla,aruanruan/scylla,duarten/scylla,respu/scylla,shaunstanislaus/scylla