Remove few refercences left to tempest-lib

A few places in docs / comments still refer to tempest-lib.
Cleaning those up.

Change-Id: I6a15a6e7e58a49a39b3955c60e16d0c196ec154c
diff --git a/tempest/hacking/checks.py b/tempest/hacking/checks.py
index d0e1fcb..5943adf 100644
--- a/tempest/hacking/checks.py
+++ b/tempest/hacking/checks.py
@@ -141,7 +141,7 @@
     """
     if TESTTOOLS_SKIP_DECORATOR.match(logical_line):
         yield (0, "T109: Cannot use testtools.skip decorator; instead use "
-               "decorators.skip_because from tempest-lib")
+               "decorators.skip_because from tempest.lib")
 
 
 def _common_service_clients_check(logical_line, physical_line, filename,