[9.x swarm] Improve stability of test "cli_selected_nodes_deploy"

[Sergey Novikov]

Detailed bug description:
The issue was found by https://product-ci.infra.mirantis.net/job/9.x.system_test.ubuntu.command_line/183/testReport/(root)/cli_node_deletion_check/

Sometimes tests from https://github.com/openstack/fuel-qa/blob/stable/mitaka/fuelweb_test/tests/test_cli.py#L92 delete controller node instead compute node. Thus, remaining nodes lose a connectivity to repos.

The reason is the wrong supposition that devops nodes are registered by nailgun according to their devops order (slave-01 gets id "1" in nailgun, slave-2 gets id "2", etc.)

https://github.com/openstack/fuel-qa/blob/stable/mitaka/fuelweb_test/tests/test_cli.py#L131-L132
https://github.com/openstack/fuel-qa/blob/stable/mitaka/fuelweb_test/tests/test_cli.py#L301-L320