Bug 1265935

Description of problem:
Host Qos - engine should block operation when configuring more than 75% of the link's effective speed

It is relatively easy to achieve unpredictable network behavior via QoS
configuration, either by having mixed QoS configuration on a logical link
(i.e. some networks with QoS, some without) or by over-committing (i.e. having
the sum of "real time" traffic required by networks on a logical link surpass
the link's capabilities). Therefore, these situations will be blocked by the
engine; either none or all the networks on a logical link must have QoS
configured, and the sum of the networks' committed rate must not surpass 75%
of the link's effective speed.

http://www.ovirt.org/Features/Detailed_Host_Network_QoS

Version-Release number of selected component (if applicable):
3.6.0-0.16.master.el6

How reproducible:
100

Steps to Reproduce:
1. Attach 2 vlan networks on NIC(1G) via Setup networks 
2. assign an anonymous Qos to one network with Weight share -15, rate limit-10 and committed rate -10.
assign an anonymous Qos to second network with weighted share- 100, rate limit-1023 and committed rate-1023
3. Approve operation

Actual results:
Succeeded to approve operation.

Expected results:
Such situation should be blocked by engine.