el6 machines fail to boot

[nvgoldin]

It was reported by @danielBelenky that el6 machines fail to boot, I can replicate it on my env with this simple init file:

domains:
  lago-basic-suite-3-6-engine:
    vm-type: ovirt-engine
    memory: 4096
    nics:
      - net: lago-basic-suite-3-6-net-management
    disks:
      - template_name: el6-base
        type: template
        name: root
        dev: vda
        format: qcow2
    metadata:
      ovirt-engine-password: 123

nets:
  lago-basic-suite-3-6-net-management:
    type: nat
    dhcp:
      start: 100
      end: 254
    management: true
    dns_domain_name: lago.local

Investigating.

[nvgoldin]

1. Looks like https://github.com/lago-project/lago/commit/179f5114fdca004fd8a0b8e40e6a166813a5a86d is the cause, for some reason el6 doesn't behave nicely with the virtio-console.
2. It was reported that after a while(around 15 minutes) the VM does actually come up, unfortunately I was unable to reproduce that locally yet in order to extract the logs.

[mykaul]

Perhaps EL6 does not have virtio-console devices?

(Why do we care about EL6 anyway?)

[nvgoldin]

Perhaps EL6 does not have virtio-console devices?

Checking.. Anyways, Instead of reverting, I'll try diverging the el6 domain XML to a different template, so we don't have to use EL6 compatibility as a common-ground.

(Why do we care about EL6 anyway?)

OST basic-suite-3.6 uses EL6 for the engine(host are already EL7).

[mykaul]

We can remove OST basic-suite-3.6.