Fix bug in call to callGetPreferredAllocationIfAvailable()

Previously, we were passing the variable 'devices' to this function,
when we should have been passing 'allocated'. This bug crept in due to a
variable name change that didn't propogate its way through the entire
function. The tests added in the previous commit would have caught this.

Author: klueska

pkg/kubelet/cm/devicemanager/manager.go

@@ -730,7 +730,7 @@ func (m *ManagerImpl) devicesToAllocate(podUID, contName, resource string, requi
 
 	// Then give the plugin the chance to influence the decision on any
 	// remaining devices to allocate.
-	preferred, err := m.callGetPreferredAllocationIfAvailable(podUID, contName, resource, available.Union(devices), devices, required)
+	preferred, err := m.callGetPreferredAllocationIfAvailable(podUID, contName, resource, available.Union(allocated), allocated, required)
 	if err != nil {
 		return nil, err
 	}