Description of problem:
Different speed reported for network vlan interface between  /sys/class/net/*/speed and vdsm-client Host getStats

-> oVirt Engine raises a warning when network threshold is over 100%, although 10 Gbit link is only utilized over 1 Gbit.


Version-Release number of selected component (if applicable):
oVirt                   4.2.5
vdsm.x86_64             4.20.35-1.el7
vdsm-common.noarch      4.20.35-1.el7
ovirt-release42.noarch  4.2.5.1-1.el7


How reproducible:
Vlan interface on a 10 Gbit link and utilization is over 1 Gbit
100 % reproducable


Steps to Reproduce:
1. 10 Gbit network card
2. 1 or several VLANs on it
3. Copy data over VLAN with over 120 MB/s

Actual results:
In Engine:
Warning: Host xxx has network interface which exceeded the defined threshold [95%] (enp10s0.100: transmit rate[1%], receive rate [100%])


Expected results:
No warning raised


Additional info:
Example:
cat /sys/class/net/enp9s0/speed
10000

cat /sys/class/net/enp9s0.80/speed
10000

cat /sys/class/net/vm-int-nfs/speed
cat: /sys/class/net/vm-int-nfs/speed: Invalid argument     <- this is the bridge for the VMs

vdsm-client Host getStats ->
...
        "enp9s0": {
            "rxErrors": "0", 
            "name": "enp9s0", 
            "tx": "3335325754762", 
            "txDropped": "0", 
            "sampleTime": 1535970960.602359, 
            "rx": "5916567956502", 
            "txErrors": "0", 
            "state": "up", 
            "speed": "10000", 
            "rxDropped": "0"
        }, 
...
        "enp9s0.80": {
            "rxErrors": "0", 
            "name": "enp9s0.80", 
            "tx": "3180024039398", 
            "txDropped": "0", 
            "sampleTime": 1535970960.602359, 
            "rx": "5669421065686", 
            "txErrors": "0", 
            "state": "up", 
            "speed": "1000", 
            "rxDropped": "0"
        }, 
...
        "vm-int-nfs": {
            "rxErrors": "0", 
            "name": "vm-int-nfs", 
            "tx": "508", 
            "txDropped": "0", 
            "sampleTime": 1535970960.602359, 
            "rx": "4428568", 
            "txErrors": "0", 
            "state": "up", 
            "speed": "1000", 
            "rxDropped": "0"
        }, 
...