Augeas will fail if the section is missing

This is a potential regression introduced in
6e049d4. If the `[shclustering]` is
completely missing from the `server.conf`, this augeas rule will fail to
create it.

Even if it is not a practical regression for a Splunk deployment, it's a
nice to make it complete for the benefit of anyone referring to this
code in the future.

Author: chutzimir

manifests/server/shclustering.pp

@@ -64,6 +64,7 @@
             lens    => 'Splunk.lns',
             incl    => "${splunk_home}/etc/system/local/server.conf",
             changes => [
+              "set target[. = 'shclustering'] 'shclustering'",
               "set target[. = 'shclustering']/mgmt_uri https://${::fqdn}:8089",
             ],
           }