Issue #60: Fix task that sets the new root user password.

tasks/secure-installation.yml

@@ -4,13 +4,22 @@
   register: mysql_root_hosts
   changed_when: false
 
+# TODO: This is currently not idempotent.
 - name: Update MySQL root password for localhost root account.
-  mysql_user:
-    name: "root"
-    host: "{{ item }}"
-    password: "{{ mysql_root_password }}"
+  shell: >
+    mysql -u root -NBe
+    'SET PASSWORD FOR "{{ mysql_root_username }}"@"{{ item }}" = PASSWORD("{{ mysql_root_password }}");'
   with_items: mysql_root_hosts.stdout_lines
 
+# The below task doesn't work in some instances for some users, at least with
+# certain versions of Ansible.
+# - name: Update MySQL root password for localhost root account.
+#   mysql_user:
+#     name: "{{ mysql_root_username }}"
+#     host: "{{ item }}"
+#     password: "{{ mysql_root_password }}"
+#   with_items: mysql_root_hosts.stdout_lines
+
 # Has to be after the root password assignment, for idempotency.
 - name: Copy .my.cnf file with root password credentials.
   template: