simplify service template syntax

roles/mediavault/templates/systemd-backup-service.j2

@@ -3,7 +3,12 @@ Description=backup-{{ item['name'] }}
 
 [Service]
 Type=oneshot
-ExecStart={{ mv_script_path }} --rsync-set-flags "{% if item['rsync_flags'] is defined %}{{ item['rsync_flags'] }}{% else %}{{ mv_rsync_flags }}{% endif %}" --strategy "{% if item['retention_strategy'] is defined %}{{ item['retention_strategy'] }}{% else %}{{ mv_retention_strategy }}{% endif %}" {% if item['src_host'] is defined and item['src_host'] %}{{ item['src_host'] }}:{% endif %}{% if item['src_dir'] is defined %}{{ item['src_dir'] }}{% else %}{{ mv_src_dir }}{% endif %} {% if item['dest_host'] is defined and item['dest_host'] %}{{ item['dest_host'] }}:{% endif %}{% if item ['dest_dir'] is defined %}{{ item['dest_dir'] }}{% else %}{{ mv_base_dir }}/{{ item['name'] }}{% endif %} {{ mv_base_dir }}/{% if item['exclude_list_name'] is defined %}{{ item['exclude_list_name'] }}{% else %}{{ mv_exclude_list_name }}{% endif %}.txt
+ExecStart={{ mv_script_path }} \
+  --rsync-set-flags "{{ item['rsync_flags'] | d(mv_rsync_flags) }}" \
+  --strategy "{{ item['retention_strategy'] | d(mv_retention_strategy) }}" \
+  {% if item['src_host'] | d() %}{{ item['src_host'] }}:{% endif %}{{ item['src_dir'] | d(mv_src_dir) }} \
+  {% if item['dest_host'] | d() %}{{ item['dest_host'] }}:{% endif %}{{ item['dest_dir'] | d(mv_base_dir + '/' + item['name']) }} \
+  {{ mv_base_dir }}/{{ item['exclude_list_name'] | d(mv_exclude_list_name) }}.txt
 {% if mv_mailer_enabled %}
 OnFailure={{ mv_mailer_service_name }}@%n.service
 {% endif %}

roles/mediavault/templates/systemd-backup-timer.j2

@@ -2,7 +2,7 @@
 Description=backup-{{ item['name'] }}-timer
 
 [Timer]
-OnCalendar={% if item['timer_calendar'] is defined %}{{ item['timer_calendar'] }}{% else %}{{mv_backup_timer_calendar }}{% endif %}
+OnCalendar={{ item['timer_calendar'] | d(mv_backup_timer_calendar) }}
 
 
 [Install]