Description of problem:
I did upgrade on RHEL 6 hypervisor and then host activation failed with message:
"Host belka is installed with VDSM version (4.14) and cannot join cluster IDM_BRQ which is compatible with VDSM versions [4.13, 4.9, 4.11, 4.12, 4.10]."

Version-Release number of selected component (if applicable):
rhevm-3.3.2-0.50.el6ev.noarch
vdsm-4.14.7-3.el6ev.x86_64

How reproducible:
100 %

Steps to Reproduce:
1. Install RHEV rhevm-3.2.6-0.50.el6ev.noarch
2. Install hypervisor with VDSM < vdsm-4.14.7-3.el6ev.x86_64. Now RHEV and hypervisor work together.
3. Upgrade VDSM to vdsm-4.14.7-3.el6ev.x86_64 and try to activate the host.

Actual results:
Error "Host belka is installed with VDSM version (4.14) and cannot join cluster IDM_BRQ which is compatible with VDSM versions [4.13, 4.9, 4.11, 4.12, 4.10]."

Expected results:
Ordinary 'yum upgrade' on RHEL 6.z hypervisor should not break existing environment. Even the erratum text (with VDSM) doesn't mention it.

Additional info:
Upgrade to rhevm-3.3.3-0.52.el6ev.noarch allowed me to activate the hypervisor.