systemctl show rc changes across versions

to avoid different errors across versions, ignore rc in favor of
found/notfound

fixes #5710

lib/ansible/modules/system/systemd.py

@@ -272,15 +272,13 @@ def main():
         if rc != 0:
             module.fail_json(msg='failure %d during daemon-reload: %s' % (rc, err))
 
-    # check service data
-    (rc, out, err) = module.run_command("%s show '%s'" % (systemctl, unit))
-    if rc != 0:
-        module.fail_json(msg='failure %d running systemctl show for %r: %s' % (rc, unit, err))
-
     found = False
     is_initd = sysv_exists(unit)
     is_systemd = False
 
+    # check service data, cannot error out on rc as it changes across versions, assume not found
+    (rc, out, err) = module.run_command("%s show '%s'" % (systemctl, unit))
+    if rc == 0:
         # load return of systemctl show into dictionary for easy access and return
         multival = []
         if out:
@@ -310,7 +308,6 @@ def main():
             if is_systemd and 'LoadError' in result['status']:
                 module.fail_json(msg="Error loading unit file '%s': %s" % (unit, result['status']['LoadError']))
 
-
     # Does service exist?
     found = is_systemd or is_initd
     if is_initd and not is_systemd: