Do symlinks & ensure-dirs together in cluster upgrade
Do symlinks & ensure-dirs together in cluster upgrade

This saves another round of sequential ssh scans over each cluster node,
and gives us another opportunity to rollback to the previous version if
the upgrade fails.

Signed-off-by: Brian Foley <a00e555871a6a538e97f8c44307104c884f8e869@google.com>
Reviewed-by: Viktor Bachraty <a13ea37fcfcda126dc54f94389ded93f402eee93@google.com>

ganeti/ganeti,leshchevds/ganeti,andir/ganeti,onponomarev/ganeti,ganeti/ganeti,yiannist/ganeti,ganeti/ganeti,andir/ganeti,mbakke/ganeti,leshchevds/ganeti,onponomarev/ganeti,yiannist/ganeti,leshchevds/ganeti,yiannist/ganeti,mbakke/ganeti,mbakke/ganeti,andir/ganeti