Description of problem:
Communication between hosts with a different IP stack (only IPv4, only IPv6 or both enabled) can fails.
for example during VM migration


Version-Release number of selected component (if applicable):
4.3.0-0.6.alpha2.el7

How reproducible:
100%

Steps to Reproduce:
1. In host-1 go to: Compute | Hosts | Network Interfaces | Setup Host Networks
2. Edit 'ovirtmgmt' attached to NIC
3. Enable IPv6 and IPv4
4. In host-2 go to the same place and enable only IPv4, IPv6 is disabled
5. At the DNS, make sure both hosts are resolved to both IPv4 & IPv6
6. Run VM on host-1
7. Try to migrate VM from host-1 to host-2

Actual results:
Migration fails

Expected results:
Migration should success or
The system should alert about the mismatch

Additional info:
1. Migration from host-2 to host-1 is working
2. The error at the log is: "No route to host"
3. It found that it is a dual-stack issue, the host that supports both, Ipv4 and IPv6 is trying to open an IPv6 connection to the host that support only IPv4, and fails
4. If FQDN of target host will be resolved to IPv4 then migration will succeed