Description of problem:


Version-Release number of selected component (if applicable):
OCP 3.11
CNV 1.3

How reproducible:
always

Steps to Reproduce:
1. create a preset with label and set memory to 64M
$ cat vmi-preset-small.yaml 
apiVersion: kubevirt.io/v1alpha2
kind: VirtualMachineInstancePreset
metadata:
  creationTimestamp: null
  name: vmi-preset-small
spec:
  domain:
    devices: {}
    machine:
      type: ""
    resources:
      requests:
        memory: 64M
  selector:
    matchLabels:
      kubevirt.io/vmPreset: vmi-preset-small

2.create vmi with label and set memory to 128M: 
apiVersion: kubevirt.io/v1alpha2
kind: VirtualMachineInstance
metadata:
  creationTimestamp: null
  labels:
    special: vmi-preset
    kubevirt.io/vmPreset: vmi-preset-small
  name: vmi-preset
spec:
  domain:
    devices:
      disks:
      - disk:
          bus: virtio
        name: registrydisk
        volumeName: registryvolume
    machine:
      type: ""
    resources:
      requests:
        memory: 128M
  terminationGracePeriodSeconds: 0
  volumes:
  - name: registryvolume
    registryDisk:
      image: kubevirt/cirros-registry-disk-demo:latest
status: {}


3.when vmi running, check status of vmi
$kubectl describe vmi vmi-preset

Actual results:
$kubectl describe vmi vmi-preset
Name:         vmi-preset
Namespace:    default
Labels:       kubevirt.io/nodeName=cnv-executor-zpengds13-node1.example.com
              kubevirt.io/vmPreset=vmi-preset-small
              special=vmi-preset
Annotations:  <none>
API Version:  kubevirt.io/v1alpha2
Kind:         VirtualMachineInstance
Metadata:
  Creation Timestamp:  2018-10-24T05:37:54Z
  Finalizers:
    foregroundDeleteVirtualMachine
  Generation:        1
.....

and run kubectl get event
no log like this:
Unable to apply VirtualMachineInstancePreset 'vmi-preset-small': spec.resources.requests[memory]: {{64 6} {<nil>} 64M DecimalSI} != {{128 6} {<nil>} 128M

Expected results:
in vmi should have:
Annotations:  virtualmachinepreset.kubevirt.io/vmi-preset-small=kubevirt.io/v1alpha2

in event log should have:
Unable to apply VirtualMachineInstancePreset 'vmi-preset-small': spec.resources.requests[memory]: {{64 6} {<nil>} 64M DecimalSI} != {{128 6} {<nil>} 128M

Additional info: