[estats] regenerate ssh host keys for estats-{2..12} so that each node has a different one.

for d in 172.16.121.{2..12}; do
 rm $d/*
 for t in ecdsa ed25519 rsa; do
   ssh-keygen -t $t -f $d/ssh_host_${t}_key -N "" -C "estats-${d##*.}.toulouse.grid5000.fr"
 done
done