sstables: update stats when writing tombstones
sstables: update stats when writing tombstones

Signed-off-by: Raphael S. Carvalho <1e2942cea40e3b4d2162dfcd9e53e41c05a84d22@cloudius-systems.com>

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