Fix file permissions with initialize-urandom element

We overlooked setting up the proper permission on both our
initialize-urandom python and systemd scripts.

Change-Id: I6da27a049954961c9333ebeb48382f8b175dc2d9
Signed-off-by: Paul Belanger <pabelanger@redhat.com>

nodepool/elements/initialize-urandom/post-install.d/80-initialize-urandom

@@ -8,6 +8,7 @@ set -o pipefail
 
 case "$DIB_INIT_SYSTEM" in
     systemd)
+        sudo chmod 0644 /usr/lib/systemd/system/initialize-urandom.service
         systemctl enable initialize-urandom.service
         ;;
     *)