Description of problem:
Rebooting a host cause a VDSNetworkException on the engine.
As a result, the host get a faulty "none responding" status forever (tested for more than 15 hours) on engine's admin GUI   

Version-Release number of selected component (if applicable):
Red Hat Enterprise Virtualization Manager Version: 3.5.0-0.13.beta.el6ev
vdsm: vdsm-4.16.5-2.el6ev.x86_64


How reproducible:
Happens all the time.

Steps to Reproduce:
Setup : up and running engine with 1 host.
1.on the host , run "reboot"
2.wait for vdsm service to be up + some reasonable idle time for update (some 5 min !?) 
3. check engine, for a clear log
4. check host status on engine's admin GUI - should be OK (green) 

Actual results:
Exception on engine's log : 
VDSNetworkException: Message timeout which can be caused by communication issues  
On engine's Admin GUI :
- Host status is read
- repeated msg on engines event log "Host1 is not responding ..."
 
Expected results:
- sometime after the host is up and running, the host status should be OK on admin's GUI , and no exceptions on engines log.


Additional info:
- restarting engine service (by "service ovirt-engine restart"), and the host seems OK again.
This bug blocks Automation tests that reboot the hosts.