Fixes ansible shell with pipefail

pipefail requires bash.
default dash shell on Debian errors out when this option is set.

(cherry picked from commit 832ba66)

CHANGELOG.rst

@@ -100,6 +100,9 @@ General
   The modern project layout supports multiple Ansible inventories encapsulated
   into :ref:`infrastructure views <project_infrastructure_views>`.
 
+- Various roles which use the ``shell`` Ansible module will now use
+  :command:`bash` shell as the executable explicitly.
+
 :ref:`debops.apt` role
 ''''''''''''''''''''''
 

ansible/roles/controller/handlers/main.yml

@@ -14,6 +14,8 @@
   become: '{{ controller__install_systemwide|bool }}'
   shell: |
     type debops-update > /dev/null 2>&1 && (echo 'debops-update' | batch > /dev/null 2>&1) || true
+  args:
+    executable: 'bash'
   when: (not controller__update_method == 'sync' and
          (ansible_local|d() and ansible_local.atd|d() and
           ansible_local.atd.enabled|bool))

ansible/roles/owncloud/tasks/tarball.yml

@@ -55,7 +55,7 @@
              | sed --silent 's/.*href="nextcloud-\({{ owncloud__release | regex_escape() }}[^"]\+\).zip.asc".*/\1/p'
              | sort --version-sort --reverse
       args:
-        executable: 'sh'
+        executable: 'bash'
       register: owncloud__register_full_version
       changed_when: False
       check_mode: False
@@ -94,7 +94,7 @@
                     + owncloud__variant + "-" + owncloud__register_full_version.stdout_lines[0]
                     + ".zip.sha512" }} | grep '.zip$'
       args:
-        executable: 'sh'
+        executable: 'bash'
       changed_when: False
       register: owncloud__register_checksum
       when: not ansible_check_mode  # Latest checksum file may not be available

ansible/roles/postwhite/handlers/main.yml

@@ -12,4 +12,6 @@
 - name: Update Postwhite in the background using batch
   shell: |
     echo '/usr/local/lib/postwhite' | batch > /dev/null 2>&1
+  args:
+    executable: 'bash'
   when: postwhite__initial_update_method == 'batch'