Do not have heat to connect to external service

The test_templates_negative haves heat to connect to an external
service. www.example.com is a registered exisitng domain,
and it also has an AAAA record.

This negative tests have heat to download a `template` from the
example.com .

If you have IPv6 local network, but you do not have a real outside
connectiviy over IPv6 this test tooks a lot of time (~2 minute).

Tempest should not have hardcoded urls for anytinhg,
what the services will use.

This change simply removes the host name from the `bad` urls,
to be deterministicly bad.

Alternatively would be adding extra config options.

Change-Id: Ib198164e544a2bf8426778e39bb616aaa468087c
diff --git a/tempest/api/orchestration/stacks/test_templates_negative.py b/tempest/api/orchestration/stacks/test_templates_negative.py
index 24e10dd..f8245c1 100644
--- a/tempest/api/orchestration/stacks/test_templates_negative.py
+++ b/tempest/api/orchestration/stacks/test_templates_negative.py
@@ -27,7 +27,7 @@
     Type: AWS::IAM::User
 """
 
-    invalid_template_url = 'http://www.example.com/template.yaml'
+    invalid_template_url = 'http:///template.yaml'
 
     @classmethod
     def resource_setup(cls):
@@ -57,4 +57,4 @@
 }
 """
 
-    invalid_template_url = 'http://www.example.com/template.template'
+    invalid_template_url = 'http:///template.template'