testplan2html: allow testplan to override the test name

When we run the same test multiple times in a plan, it might be
convenient to use different names.

Signed-off-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>
diff --git a/plans/testplan2html.py b/plans/testplan2html.py
index 746df4d..58d967b 100755
--- a/plans/testplan2html.py
+++ b/plans/testplan2html.py
@@ -135,7 +135,8 @@
         test.prepend("os", test_yaml['metadata']['os'])
         test.prepend("scope", test_yaml['metadata']['scope'])
         test.prepend("description", test_yaml['metadata']['description'])
-        test.prepend("name", test_yaml['metadata']['name'])
+        if 'name' not in test:
+            test.prepend("name", test_yaml['metadata']['name'])
     else:
         render(test_yaml, templates_dir=args.templates_directory, template=args.test_template_name, name=test_path)
     return not test['missing']