Fix cluster rename and known_hosts
Fix cluster rename and known_hosts

This patch rewrites and distributes ganeti's known_hosts file in case of
a cluster rename.

We also fix a problem in the node add (from where I copied the
known_hosts file distribution).

Reviewed-by: ultrotter


ganeti/ganeti,bitemyapp/ganeti,onponomarev/ganeti,apyrgio/snf-ganeti,ganeti/ganeti,yiannist/ganeti,dimara/ganeti,apyrgio/ganeti,grnet/snf-ganeti,apyrgio/snf-ganeti,leshchevds/ganeti,yiannist/ganeti,onponomarev/ganeti,grnet/snf-ganeti,ganeti/ganeti,andir/ganeti,mbakke/ganeti,bitemyapp/ganeti,mbakke/ganeti,apyrgio/ganeti,andir/ganeti,yiannist/ganeti,leshchevds/ganeti,ganeti-github-testing/ganeti-test-1,mbakke/ganeti,leshchevds/ganeti,ganeti-github-testing/ganeti-test-1,andir/ganeti,dimara/ganeti