Heat: use first_address instead of first_private_address

first_private_address no longer exists in OS::Nova::Server
as it was a misconceived feature.

Change-Id: Id1a0eeca1bf3b57c27e6b93ae64e11d3de9b771e
Related-Bug: #1228929
diff --git a/tempest/api/orchestration/stacks/test_server_cfn_init.py b/tempest/api/orchestration/stacks/test_server_cfn_init.py
index d8334fa..ea0bff5 100644
--- a/tempest/api/orchestration/stacks/test_server_cfn_init.py
+++ b/tempest/api/orchestration/stacks/test_server_cfn_init.py
@@ -122,7 +122,7 @@
   SmokeServerIp:
     Description: IP address of server
     Value:
-      Fn::GetAtt: [SmokeServer, first_private_address]
+      Fn::GetAtt: [SmokeServer, first_address]
 """
 
     @classmethod