Description of problem:
NPE is thrown when trying configuring networks on a host with VDSM version higher than the engine one. That happens because the code tries to a config value for the host version, which is not exists in the engine DB (as that is considered as a future one relative to the engine), instead of checking cluster support level (which could not be unknown/new to the engine).

Version-Release number of selected component (if applicable):
engine 3.6
vdsm - master (4.0)

How reproducible:
100%

Steps to Reproduce:
1. Install a v4.0 host to engine 3.6
2. try to open setup networks dialog for the newly installed host
3.

Actual results:
The gear spins endlessly an NPE appears in the browser console log.

Expected results:
An exception should not be thrown and the dialog should appear flawlessly.

Additional info:
The NPE happens in org.ovirt.engine.ui.uicommonweb.models.hosts.network.NetworkOperationFactory:138 when trying cast the null value returned by AsyncDataProvider.isNetworkExclusivenessPermissiveValidation.