switch to tempest lib from tempest_lib

due to changes in tempest framework, we are using
tempest lib instead of tempest_lib.

Change-Id: I3e5e5158c0b1d2b598d4a744ccd9041a7dc3ec77

networking_l2gw/tests/api/test_l2gw_extensions.py

@@ -17,7 +17,7 @@ from tempest import test
 
 from neutron.tests.api import base
 
-from tempest_lib.common.utils import data_utils
+from tempest.lib.common.utils import data_utils
 
 from networking_l2gw.tests.api import base_l2gw
 from networking_l2gw.tests.tempest import config

networking_l2gw/tests/api/test_l2gw_negative.py

@@ -24,8 +24,8 @@ from oslo_config import cfg
 
 from random import randint
 
-from tempest_lib.common.utils import data_utils
-from tempest_lib import exceptions as lib_exc
+from tempest.lib.common.utils import data_utils
+from tempest.lib import exceptions as lib_exc
 
 
 CONF = cfg.CONF