Add security

- In case other devices pop up under the produce-Name.0

includes/discovery/os/ibmtl.inc.php

@@ -12,7 +12,7 @@
 
 if (!$os) {
     $ibmtl_snmpget = snmp_get($device, 'SML-MIB:product-Name.0', '-Oqv', '');
-    if (!empty($ibmtl_snmpget)) {
+    if (stristr($ibmtl_snmpget, 'IBM System Storage TS3500 Tape Library')) {
         $os = 'ibmtl';
     }
 }