remove any duplicate jobs when locking

Netdisco/lib/App/Netdisco/JobQueue/PostgreSQL.pm

@@ -109,6 +109,15 @@ sub jq_lock {
       schema('netdisco')->resultset('Admin')
         ->find($job->id, {for => 'update'})
         ->update({ status => "queued-$fqdn" });
+
+      # remove any duplicate jobs, needed because we have race conditions
+      # when queueing jobs of a type for all devices
+      schema('netdisco')->resultset('Admin')->search({
+        device    => $job->device,
+        port      => $job->port,
+        action    => $job->action,
+        subaction => $job->subaction,
+      }, {for => 'update'})->delete();
     });
     $happy = true;
   };