Make tempest accounts independent from devstack

Changes the default for tempest accounts to None, so they
are in no way specific to devstack as they are now.

Fixes bug 1287191

Change-Id: Iac805dc4816a3029ad2f68448d9e735b213b5154
diff --git a/etc/tempest.conf.sample b/etc/tempest.conf.sample
index b0c7826..e17da7a 100644
--- a/etc/tempest.conf.sample
+++ b/etc/tempest.conf.sample
@@ -307,14 +307,14 @@
 
 # Administrative Username to use for Nova API requests.
 # (string value)
-#username=admin
+#username=<None>
 
 # Administrative Tenant name to use for Nova API requests.
 # (string value)
-#tenant_name=admin
+#tenant_name=<None>
 
 # API key to use when authenticating as admin. (string value)
-#password=pass
+#password=<None>
 
 
 [compute-feature-enabled]
@@ -451,16 +451,16 @@
 #endpoint_type=publicURL
 
 # Username to use for Nova API requests. (string value)
-#username=demo
+#username=<None>
 
 # Tenant name to use for Nova API requests. (string value)
-#tenant_name=demo
+#tenant_name=<None>
 
 # Role required to administrate keystone. (string value)
 #admin_role=admin
 
 # API key to use when authenticating. (string value)
-#password=pass
+#password=<None>
 
 # Username of alternate user to use for Nova API requests.
 # (string value)
@@ -476,14 +476,14 @@
 
 # Administrative Username to use for Keystone API requests.
 # (string value)
-#admin_username=admin
+#admin_username=<None>
 
 # Administrative Tenant name to use for Keystone API requests.
 # (string value)
-#admin_tenant_name=admin
+#admin_tenant_name=<None>
 
 # API key to use when authenticating as admin. (string value)
-#admin_password=pass
+#admin_password=<None>
 
 
 [identity-feature-enabled]