Resolved bug where $text would use the previous iteration if $sla_type was unknown.

Now set a default $text value which will be over written if $sla_type is known.

html/pages/device/slas.inc.php

@@ -9,6 +9,9 @@ $slas = dbFetchRows('SELECT * FROM `slas` WHERE `device_id` = ? AND `deleted` =
 // Collect types
 $sla_types = array('all' => 'All');
 foreach ($slas as $sla) {
+    // Set a default type, if we know about it, it will be overwritten below.
+    $text = 'Unknown';
+
     $sla_type = $sla['rtt_type'];
 
     if (!in_array($sla_type, $sla_types)) {