And try to disable upload when there are local modifications.

Also depend on redhat-cluster-pve

because the service is called /etc/init.d/cman (although the
binary running is corosync)

we have nothing to display there (for now, we can re-add later)

we can now set the language in the datacenter config file,
but the value is not used (we still have no i18n)

it seems that apache doesn not log error to the error log, so we catch
them an log to syslog