db/system_keyspace: Fix use-after-free in build_dc_rack_info()
db/system_keyspace: Fix use-after-free in build_dc_rack_info()

Fixes #264.

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

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