show FQDN first in /etc/hosts (closes: #3521) (#3522)

The hosts(5) manpage clearly states that the first entry is the
"canonical name", or FQDN (Fully-Qualified Domain Name):

    IP_address canonical_hostname [aliases...]

By using the alias as a first entry, `hostname -f` does not return the
correct domain which breaks all sorts of unrelated functionality (it
has impact over email server configuration, for example).

roles/kubernetes/preinstall/tasks/0090-etchosts.yml

@@ -3,7 +3,7 @@
   blockinfile:
     dest: /etc/hosts
     block: |-
-      {% for item in (groups['k8s-cluster'] + groups['etcd'] + groups['calico-rr']|default([]))|unique -%}{{ hostvars[item]['access_ip'] | default(hostvars[item]['ip'] | default(hostvars[item]['ansible_default_ipv4']['address'])) }}{% if (item != hostvars[item]['ansible_hostname']) %} {{ hostvars[item]['ansible_hostname'] }} {{ hostvars[item]['ansible_hostname'] }}.{{ dns_domain }}{% endif %} {{ item }} {{ item }}.{{ dns_domain }}
+      {% for item in (groups['k8s-cluster'] + groups['etcd'] + groups['calico-rr']|default([]))|unique -%}{{ hostvars[item]['access_ip'] | default(hostvars[item]['ip'] | default(hostvars[item]['ansible_default_ipv4']['address'])) }}{% if (item != hostvars[item]['ansible_hostname']) %} {{ hostvars[item]['ansible_hostname'] }}.{{ dns_domain }} {{ hostvars[item]['ansible_hostname'] }}{% endif %} {{ item }} {{ item }}.{{ dns_domain }}
       {% endfor %}
     state: present
     create: yes