Install python-netaddr, needed by platform-install

Change-Id: I8a8fe90d19a0f6a9a60fb3cf92d4b858d2bf7297
diff --git a/ansible/roles/common/defaults/main.yml b/ansible/roles/common/defaults/main.yml
index 818be64..4bc74b9 100644
--- a/ansible/roles/common/defaults/main.yml
+++ b/ansible/roles/common/defaults/main.yml
@@ -7,6 +7,7 @@
   - debian-keyring
   - debian-archive-keyring
   - rng-tools
+  - python-netaddr
 
 obsolete_services:
   - puppet