Fix format of curtin:xenial:amd64

Closes-bug: PROD-25243 (PROD:25243)

Change-Id: Ifd5f3f9204f53a322d955f6d33419d6a696bd594
diff --git a/tests/pillar/maas_region.sls b/tests/pillar/maas_region.sls
index d601e91..d3325eb 100644
--- a/tests/pillar/maas_region.sls
+++ b/tests/pillar/maas_region.sls
@@ -10,9 +10,13 @@
       curtin_vars:
         amd64:
           xenial:
-            extra_pkgs: [ "curl", "wget" ]
-            #kernel_package: 'linux-image-virtual-hwe-16.04'
-            kernel_package: 'mc'
+            extra_pkgs:
+              enabled: true
+              pkgs: [ "curl", "wget" ]
+            kernel_package:
+              enabled: true
+              #value: 'linux-image-virtual-hwe-16.04'
+              value: 'mc'
   region:
     enabled: true
     bind: