Description of problem:
When deploying an iSCSI multipath bond, user has to add networks to it as initiators. 
If required networks are added to the bond, it will lead to a situation which the host will be moved to non-operational state if it looses only one of its networks configured in the iSCSI bond. It happens because required networks are mandatory for the cluster and if one of them is down in the host, the host won't be operational, even though it has other active networks.

Version-Release number of selected component (if applicable):
AV7
rhevm-3.4.0-0.15.beta3.el6ev.noarch

How reproducible:
Always

Steps to Reproduce:
On a shared DC with 1 active iSCSI storage domain:
1. Create 2 new networks and attach them to the cluster with required check-box checked
2. Attach the networks to the cluster's hosts NICs 
3. Create a new iSCSI multipath bond (under DC tab -> pick the relevant DC -> iSCSI multipath sub-tab -> new) and add the new networks along with the targets to it
4. After the bond is set, shut-down one of the hosts NICs with is attached to one of the network in the multipath bond.


Actual results:
Required networks are possible to be added to the iSCSI multipath bond. It causes to host to become non-operational even though it has connectivity to the storage via its other networks.

Expected results:
Required networks shouldn't be allowed to be added to an iSCSI bond