monitoring/lists: Don't render unexistant controls

Even PHP code in HTML comments will be executed. As the filter object
sometimes failes, this can result in an invisible "breaking" exception.

refs #6031

modules/monitoring/application/views/scripts/list/hosts.phtml

@@ -4,7 +4,7 @@ $helper = $this->getHelper('MonitoringState');
 <div class="controls">
 <?= $this->tabs ?>
 <div style="margin: 1em;" class="dontprint">
-<!--<?= $this->filterBox ?>-->Sort by <?= $this->sortControl->render($this); ?>
+Sort by <?= $this->sortControl->render($this); ?>
 </div>
 
 <?= $this->paginationControl($hosts, null, null, array('preserve' => $this->preserve)); ?>

modules/monitoring/application/views/scripts/list/services.phtml

@@ -5,7 +5,6 @@ if (!$this->compact): ?>
 <div class="controls">
 <?= $this->tabs ?>
 <div style="margin: 1em;" class="dontprint">
-<!-- <?= $this->filterBox ?>-->
 Sort by <?= $this->sortControl ?>
 </div>