Use data_utils in tempest.lib.common.utils

Tempest tests should use the stable method defined in tempest.lib.
This patch is to use data_utils from tempest.lib.common.utils in
OAUTHConsumersV3Test and HACKING.rst.

Change-Id: Ia9f4cf37d8d57da34864a5eb55a8fe9d9c5722f5
diff --git a/HACKING.rst b/HACKING.rst
index c0a857c..cef4f21 100644
--- a/HACKING.rst
+++ b/HACKING.rst
@@ -232,9 +232,9 @@
   and xml version of the same test class there could still be a race between
   methods.
 
-- The rand_name() function from tempest.common.utils.data_utils should be used
-  anywhere a resource is created with a name. Static naming should be avoided
-  to prevent resource conflicts.
+- The rand_name() function from tempest.lib.common.utils.data_utils should be
+  used anywhere a resource is created with a name. Static naming should be
+  avoided to prevent resource conflicts.
 
 - If the execution of a set of tests is required to be serialized then locking
   can be used to perform this. See AggregatesAdminTest in