Don't check swap if not present

linux/meta/sensu.yml

@@ -1,3 +1,4 @@
+{%- from "linux/map.jinja" import storage with context %}
 check:
   local_linux_system_zombie_procs:
     command: "PATH=$PATH:/usr/lib64/nagios/plugins:/usr/lib/nagios/plugins check_procs -w 2 -c 7 -s Z"
@@ -17,12 +18,14 @@ check:
     occurrences: 1
     subscribers:
     - local-linux-system
+  {%- if storage.swap|length > 0 %}
   local_linux_storage_swap_usage:
     command: "PATH=$PATH:/usr/lib64/nagios/plugins:/usr/lib/nagios/plugins check_swap -a -w 50% -c 20%"
     interval: 60
     occurrences: 1
     subscribers:
     - local-linux-storage
+  {%- endif %}
   local_linux_storage_disk_usage:
     command: "PATH=$PATH:/usr/lib64/nagios/plugins:/usr/lib/nagios/plugins check_disk -w 15% -c 5% -p / -p /var -p /usr -p /tmp -p /var/log"
     interval: 60