Store artifacts from the remote Jenkins slave if present

- collect artifacts from the remote Jenkins slave
  if $jenkins_slave_node_name != ${NODE_NAME}

- store py.test logs into files with different names to
  avoid overwrites

Change-Id: I1ba4fe425c5400f9095e5cd8b7e3d901be01d288
diff --git a/tcp_tests/settings.py b/tcp_tests/settings.py
index f98981d..e8968be 100644
--- a/tcp_tests/settings.py
+++ b/tcp_tests/settings.py
@@ -24,6 +24,7 @@
 
 
 LOGS_DIR = os.environ.get('LOGS_DIR', os.getcwd())
+LOG_NAME = os.environ.get('LOG_NAME', 'tests.log')
 TIMESTAT_PATH_YAML = os.environ.get(
     'TIMESTAT_PATH_YAML', os.path.join(
         LOGS_DIR, 'timestat_{}.yaml'.format(time.strftime("%Y%m%d"))))