Use sudo to write dhcp hosts

The directory is created with root ownership, but then the files
are added by bifrost user. This causes to fail with permission denied.
Adding become: yes to execute this task with sudo powers.

Change-Id: Ia792033eef3553e05ca2d5df4b25cb64c7a009cb

playbooks/roles/bifrost-deploy-nodes-dynamic/tasks/main.yml

@@ -21,6 +21,7 @@
   template: src=dhcp-host.j2 dest=/etc/dnsmasq.d/bifrost.dhcp-hosts.d/{{ inventory_hostname }}
   delegate_to: localhost
   when: inventory_dhcp | bool
+  become: yes
 - name: "Sending dnsmasq HUP"
   # Note(TheJulia): We need to actually to send a hup signal directly as
   # Ansible's reloaded state does not pass through to the init script.