No longer need the ondrej MySQL PPA

(cherry picked from commit 6218350b)

playbooks/roles/mysql/tasks/mysql.yml

@@ -49,13 +49,6 @@
     update_cache: yes
   when: ansible_distribution_release == 'precise'
 
-# repo.mysql.com does not have 5.6 packages for xenial
-- name: Install MySQL from ondrej PPA
-  apt_repository:
-    repo: "ppa:ondrej/mysql-5.6"
-    update_cache: yes
-  when: ansible_distribution_release == 'xenial'
-
 - name: Install mysql-5.6 and dependencies
   apt:
     name: "{{ item }}"