Fix error in daily.php (librenms#17892)

undefined array key 'f'

Author: murrant

daily.php

@@ -16,6 +16,7 @@
 use LibreNMS\Validations\Php;
 
 $options = getopt('df:o:t:r:');
+$options['f'] = isset($options['f']) ? $options['f'] : '';
 
 /**
  * Scripts without dependencies