Fix docs for admin user config in conf sample.

Change-Id: Ie30fb4e0a6104a3b315f355566a66a366ac98383
diff --git a/etc/tempest.conf.sample b/etc/tempest.conf.sample
index 9280c57..ac18490 100644
--- a/etc/tempest.conf.sample
+++ b/etc/tempest.conf.sample
@@ -35,9 +35,9 @@
 
 # This should be the username of a user WITH administrative privileges
 admin_username = admin
-# The above non-administrative user's password
+# The above administrative user's password
 admin_password = secret
-# The above non-administrative user's tenant name
+# The above administrative user's tenant name
 admin_tenant_name = admin
 
 [compute]