Remove legacy cleanup tasks

These should have been removed in the Pike release.

Change-Id: I62fe8a2a828ef2f25608ac507e22b6d051365667

tasks/galera_server_upgrade_pre.yml

@@ -45,31 +45,3 @@
   with_items:
     - "{{ galera_server_upgrade_packages_remove }}"
 
-- name: Remove old apt sources
-  block:
-    # TODO: Remove the following three tasks in Pike
-    # They're only required during upgrades transitioning to a
-    # statically named apt sources file.
-    - name: Find old sources
-      command: >
-        grep -rnil maria /etc/apt/sources.list.d/ --exclude MariaDB.list
-      changed_when: false
-      failed_when: false
-      register: old_sources
-
-    - name: Remove old sources
-      file:
-        path: "{{ item }}"
-        state: absent
-      with_items: "{{ old_sources.stdout_lines | default([]) }}"
-
-    - name: Update apt sources (Forced)
-      apt:
-        update_cache: yes
-        cache_valid_time: 0
-      register: apt_update
-      until: apt_update is success
-      retries: 5
-      delay: 2
-  when:
-    - ansible_facts['pkg_mgr'] == "apt"