fix: sensors not being removed from database (#6169)

includes/discovery/sensors/temperature/lantronix-slc.inc.php

@@ -0,0 +1,30 @@
+<?php
+/*
+ * LibreNMS Lantronix SLC Temperature Sensor Discovery module
+ *
+ * Copyright (c) 2016 Chris A. Evans <thecityofguanyu@outlook.com>
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version.  Please see LICENSE.txt at the top level of
+ * the source code distribution for details.
+ */
+
+echo("Lantronix SLC");
+
+// Chassis temperature
+$high_limit         = 50;
+$high_warn_limit    = 45;
+$low_warn_limit     = 5;
+$low_limit          = 1;
+
+$descr    = "System Temperature:";
+$valueoid = ".1.3.6.1.4.1.244.1.1.6.25.0"; // LANTRONIX-SLC-MIB::slcSystemInternalTemp.0 = INTEGER: 24 Celsius
+$value    = snmp_get($device, 'slcSystemInternalTemp.0', '-Oqv', 'LANTRONIX-SLC-MIB');
+$value    = trim($value, 'Celsius');
+$value    = trim($value, ' ');
+
+if (is_numeric($value)) {
+    discover_sensor($valid['sensor'], 'temperature', $device, $valueoid, 1, 'lantronix-slc', $descr, '1', '1', $low_limit, $low_warn_limit, $high_warn_limit, $high_limit, $value);
+}