Contrail provisioning needs graceful error handling

[Sriram Bhamidipati]

When an incorrect name (control node name) is specified, provision_config_node.py throws an exception rather than handling gracefully. It can be improved

Traceback (most recent call last):
  File "/opt/contrail/utils/provision_config_node.py", line 165, in <module>
    main()
  File "/opt/contrail/utils/provision_config_node.py", line 161, in main
    ConfigNodeProvisioner(args_str)
  File "/opt/contrail/utils/provision_config_node.py", line 49, in __init__
    self.del_config_node()
  File "/opt/contrail/utils/provision_config_node.py", line 154, in del_config_node
    fq_name=config_node_obj.get_fq_name())
  File "/usr/lib/python2.7/dist-packages/vnc_api/vnc_api.py", line 42, in wrapper
    return func(self, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/vnc_api/vnc_api.py", line 545, in _object_delete
    res_type=res_type, fq_name=fq_name, id=id, ifmap_id=ifmap_id)
  File "/usr/lib/python2.7/dist-packages/vnc_api/vnc_api.py", line 741, in _read_args_to_id
    return (True, self.fq_name_to_id(res_type, fq_name))
  File "/usr/lib/python2.7/dist-packages/vnc_api/vnc_api.py", line 42, in wrapper
    return func(self, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/vnc_api/vnc_api.py", line 982, in fq_name_to_id
    content = self._request_server(rest.OP_POST, uri, data=json_body)
  File "/usr/lib/python2.7/dist-packages/vnc_api/vnc_api.py", line 755, in _request_server
    retry_count=retry_count)
  File "/usr/lib/python2.7/dist-packages/vnc_api/vnc_api.py", line 827, in _request
    % (op, url, data, content))
cfgm_common.exceptions.NoIdError: Unknown id: Error: oper 1 url /fqname-to-id body {"fq_name": ["default-global-system-config", "default-global-system-config"], "type": "config-node"} response Name ['default-global-system-config', 'default-global-system-config'] not found