Description of problem:
refresh caps events are not sent on network dhcp attachment or update

It's not clear yet who is not sending the event, does vdsm send event when attaching or setting network with dhcp to host and then engine doesn't sending a refresh caps to the host or maybe vdsm is not sending such event to the engine. Any how when attaching a network with dhcp bootproto or updating a network with dhcp, an event from vdsm should go to the host once network get the IP and then engine should invoke refresh caps on the host and IP should be visible in UI without any manual intervention.

Now, DEV saying that was suppose to work or used to work, but in fact this was never working and me personally was never aware of such code(there is no bug which tracking such code). I'm using rhv product for almost 4 years now and i never got an event when was setting a dhcp network on the host, i always needed to do a manual refresh caps in order to see the IP from dhcp in the UI webadmin. 

There is a confuse here between DEV and QE on this matter, further investigation is needed. And this is now may explain some of the out-of-sync bugs we have in the product. 


Version-Release number of selected component (if applicable):
4.2.4.2-0.1.el7_3
vdsm-4.20.30-1.el7ev.x86_64

How reproducible:
100% 

Steps to Reproduce:
1. Attach network with dhcp bootproto or update an attached network with dhcp
2. Approve operation

Actual results:
Nothing changes in the UI, no IP is visible. On the host dhcp allready gave an address to the network, but no event was coming, not sure from which side, engine or vdsm?
Need to do a manual refresh caps

Expected results:
When setting a network with dhcp, vdsm should send an event to the engine once network get the IP address and then engine should invoke caps in order to display the IP in the UI.

Additional info:
This maybe affecting BZ 1517638 and some other out-of-sync bugs we have.