Testcases for services failover

- keepalived restart # 4756965
- keepalived stop # 3385682

Changes:
- RallyManager refactored to use updated rally container with tempest
- Added 'rally.create_rally_task' and 'rally.run_task' methods to
  generate load on the OpenStack cluster with the specified task config
- new mark for test cases that configure 'rally' fixture:
  @pytest.mark.with_rally(rally_node=<str>,
                          prepare_openstack=<bool>,
                          prepare_tempest=<bool>)
- a new method common_services_deployed.check_keepalived_pillar()
  to check the keepalived pillar settings consistency
- a new fixture 'func_name' returns the current test function name
- a new method 'underlay.get_target_node_names(target='ctl')' to get
  a list of all nodes which name starts with the specified target string
- a new method underlay.delayed_call() which can postpone the specified
  shell command to run in several minutes later in the background
  on the specified node
- fixture 'grab_versions' now works also for failed tests

Change-Id: Icede63163ae0b3569e8463563cb548e2d314899d
diff --git a/tcp_tests/tests/system/conftest.py b/tcp_tests/tests/system/conftest.py
index a4a72a2..ec3846d 100644
--- a/tcp_tests/tests/system/conftest.py
+++ b/tcp_tests/tests/system/conftest.py
@@ -32,6 +32,7 @@
     'show_step',
     'revert_snapshot',
     'snapshot',
+    'func_name',
     # config_fixtures
     'config',
     # underlay_fixtures