Issue #1760: Make hostname role actually do what its docs say it does.

Author: geerlingguy

provisioning/roles/drupalvm.hostname/meta/main.yml

@@ -16,11 +16,7 @@ galaxy_info:
         - all
     - name: Ubuntu
       versions:
-        - precise
-        - raring
-        - saucy
-        - trusty
-        - xenial
+        - all
 
   galaxy_tags:
     - drupal

provisioning/roles/drupalvm.hostname/tasks/main.yml

@@ -3,7 +3,9 @@
   copy:
     content: "{{ hostname_fqdn }}\n"
     dest: /etc/mailname
-  when: ansible_os_family == 'Debian'
+  when:
+    - ansible_os_family == 'Debian'
+    - hostname_fqdn
 
 - name: Add hostname to /etc/hosts.
   lineinfile:
@@ -12,15 +14,19 @@
     line: "127.0.0.1\t{{ hostname_fqdn }}\t{{ hostname_short }}"
     state: present
     unsafe_writes: "{{ hostname_unsafe_writes }}"
+  when: hostname_fqdn
 
 - name: Configure hostname.
   copy:
     content: "{{ (ansible_os_family == 'Debian') | ternary(hostname_short, hostname_fqdn) }}\n"
     dest: /etc/hostname
     unsafe_writes: "{{ hostname_unsafe_writes }}"
   register: set_hostname
+  when: hostname_fqdn
 
 - name: Set the hostname for current session.
   command: hostname --file /etc/hostname
-  when: set_hostname.changed
+  when:
+    - set_hostname is changed
+    - hostname_fqdn
   tags: ['skip_ansible_lint']