db: mark newly created sstables as unshared
db: mark newly created sstables as unshared

Other shards know nothing about them, so they won't mark them for deletion
when the time comes.

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