tests: fix node variant selection

Type: fix
Fixes: 4830e4f78fb8e46b23a1a0711cd06969a77d8d95

Change-Id: Iddc73dbda633acd72bd82e52f8ae83c17e3940f6
Signed-off-by: Benoît Ganne <bganne@cisco.com>
diff --git a/test/framework.py b/test/framework.py
index 05e59b5..bfcc030 100644
--- a/test/framework.py
+++ b/test/framework.py
@@ -394,7 +394,7 @@
             coredump_size = "coredump-size unlimited"
         default_variant = config.variant
         if default_variant is not None:
-            default_variant = "defaults { %s 100 }" % default_variant
+            default_variant = "default { variant %s 100 }" % default_variant
         else:
             default_variant = ""