homeassistant: Do not apply hass-dhcp

The UniFi Security Gateway now provides DHCP for the Home Assistant
network.  This simplifies management a bit, so I do not have to manage
three DHCP servers.  The USG has firewall rules to prevent Internet
traffic.

homeassistant.yml

@@ -11,12 +11,3 @@
     service:
       name: httpd
       state: started
-
-- hosts: home-assistant
-  roles:
-  - hass-dhcp
-  tasks:
-  - name: ensure dnsmasq is running
-    service:
-      name: dnsmasq
-      state: started