Description of problem:
[OVN] - [HE] - ovn tunnel doesn't created if central hostname resolved as 127.0.0.1 in hosts file 

When running hosted engine deploy, user is asked if he want to add the VM's FQDN to /etc/hosts file and resolved as 127.0.01, if choosing 'yes' then the ovn deploy using 127.0.0.1 as central and then no ovn tunnel is created on the host/s.

 2018-05-09 10:05:42,563 p=61921 u=ovirt | TASK [ovirt-provider-ovn-driver : Configure OVN for oVirt] ********************* 2018-05-09 10:05:50,118 p=61921 u=ovirt | changed: [lynx03.lab.eng.tlv2.redhat.com] => { "changed": true, "cmd": [ "vdsm-tool", "ovn-config", "127.0.0.1", "10.46.16.22" ], "delta": "0:00:06.741161", "end": "2018-05-09 10:05:50.029649", "rc": 0, "start":
"2018-05-09 10:05:43.288488" }


Version-Release number of selected component (if applicable):
4.2.3.5-0.1.el7


How reproducible:
100% 

Steps to Reproduce:
1. Run hosted-engine deploy and choose yes to add the VM's FQDN to hosts file

Actual results:
Try to use ovn in this engine after deploy is done
NO tunnel created on the host/s

Expected results:
We should handle such use case for users that choose to add their FQDNs to hosts file and resolved as 127.0.01