[5.0 Vcenter] Contrail-vmware instance isn't launched in case one of ESXI hosts is disconnected.

[Olesia Tsvigun]

Fuel 9.0
fuel-plugin-contrail 5.0 build#688

Steps to reproduce
1. Install contrail plugin with vcenter.
2. Shutdown one ESXI host.
3. Create cluster with vcenter.
4. Fill all credentials on Vmware tab.
5. Try to run
./spawner.py --env_id 6 --spawn --reduce-vm-params

Actual result
Contrail-vmware instances were not launched on available ESXI host. Following error was displayed:
Traceback (most recent call last):
  File "./spawner.py", line 734, in <module>
    vm.create(name=vm_name, cpu=vm_cpu, memory=vm_memory, storage_name=storage_name, host=vm_host)
  File "./spawner.py", line 486, in create
    self.wait_for_tasks(self.service_instance, [task])
  File "./spawner.py", line 100, in wait_for_tasks
    raise task.info.error
pyVmomi.VmomiSupport.InvalidHostConnectionState: (vim.fault.InvalidHostConnectionState) {
   dynamicType = <unset>,
   dynamicProperty = (vmodl.DynamicProperty) [],
   msg = 'The operation is not allowed in the current connection state of the host.',
   faultCause = <unset>,
   faultMessage = (vmodl.LocalizableMessage) [],
   host = 'vim.HostSystem:host-31'

[Vitalii Kovalchuk (vkovalchuk)]

https://review.openstack.org/#/c/380186

[Olesia Tsvigun (otsvigun)]

Verified at fuel-plugin-contrail build#695