Replace depricated tempest-lib with tempest.lib

Change-Id: Ia674f69f5e5b2a94f3aac5ed497a39e6b71816c0
diff --git a/ironic_tempest_plugin/services/baremetal/base.py b/ironic_tempest_plugin/services/baremetal/base.py
index c2546d9..5b6dea8 100644
--- a/ironic_tempest_plugin/services/baremetal/base.py
+++ b/ironic_tempest_plugin/services/baremetal/base.py
@@ -15,7 +15,7 @@
 from oslo_serialization import jsonutils as json
 import six
 from six.moves.urllib import parse as urllib
-from tempest_lib.common import rest_client
+from tempest.lib.common import rest_client
 
 
 def handle_errors(f):