Database: Do a commitlog::sync_all first on stop.
Database: Do a commitlog::sync_all first on stop.

Refs #293
IFF one desires to _not_ shutdown stuff cleanly, still running this first
in database::stop will at least ensure that mutations already in CL transit
will end up on disk and be replayable

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