[5.0 Vcenter] Cluster of vcenter in not updated in the nova-compute.conf, after adding/removing cluster.

Fuel 9.0
fuel-plugin-contrail 5.0 build #585

Steps to reproduce
    1. Connect to a Fuel with preinstalled Contrail plugin.
    2. Create a new environment with following parameters:
       * Compute: vCenter
       * Networking: Neutron with tunneling segmentation
       * Storage: default
       * Additional services: default
    3. Run script that prepares vmware part for deployment (creates few Distributed
       Switches and spawns virtual machine on each ESXi node)
    4. Configure Contrail plugin settings:
       * Datastore name
       * Datacenter name
       * Uplink for DVS external
       * Uplink for DVS private
       * DVS external
       * DVS internal
       * DVS private
    5. Add nodes with following roles:
       * Controller
       * ComputeVMWare
       * Contrail-vmware
       * Contrail-config + contrail-control + contrail-db + contrail-analytics
    6. Configure interfaces on nodes.
    7. Configure network settings.
    8. Configure VMware vCenter Settings:
       Add and assign 1 vCenter cluster 'Cluster1' to compute-vmware.
    9. Deploy the cluster.
    10. Add Cluster2 via script ./spawner.py --env_id 1 --spawn --reduce-vm-params --cluster-list Cluster1,Cluster2
    11. Add ne contrail-vmware node.
    12. Deploy changes.
    13. Remove Cluster1 via script ./spawner.py --env_id 1 --spawn --reduce-vm-params --cluster-list Cluster2
    14. Deploy changes.
    15. Check nova-compute.conf on compute-vmware node.

   Actual result
   'cluster_name' is Cluster1

   Expected Result
   'cluster_name' should be Cluster2

root@node-1:/etc/nova# cat nova-compute.conf
[DEFAULT]
compute_driver=nova.virt.vmwareapi.contrailVCDriver
log_file=nova-compute-vmware-vcenter-vm1.log
host=vcenter-vm1
reserved_host_memory_mb = 0
force_config_drive=False

[vmware]

cache_prefix=$host

=Cluster1

vcenter_dvswitch=Contrail-DVS-Int

host_ip=172.16.0.145
host_username=root
host_password=vmware

insecure=True

api_retry_count=5
maximum_objects=100
task_poll_interval=5.0
datastore_regex=.*
use_linked_clone=true

[libvirt]
virt_type=vmwareapi