[litevirt] Not start collectd service during the boot.

This is a temporary workaround for this issue:

https://github.com/luohao-brian/ovirt-node/issues/4

Not a write plugin is enabled for collectd on ovirt.

Hence collectd complains about tens of warnings in /var/log/messages.

Collectd has been disabled by ovirt due to rhbz #586535, so from the
setup UI, collectd configuration(monitoring page) will take no effect.

However, anonymous users are not authenticated to login rhbz for #586535.
Merge branch 'dev.litevirt' of https://github.com/luohao-brian/ovirt-node into dev.litevirt