Fix a bug introduced into line filter code when checking stuff yesterday, a=chris

diff --git a/src/library/Utility.php b/src/library/Utility.php
index 1065829ca..541ed1138 100755
--- a/src/library/Utility.php
+++ b/src/library/Utility.php
@@ -2210,7 +2210,7 @@ function tail($file_name, $num_lines)
  */
 function lineFilter($lines, $filters)
 {
-    $out_lines = [$filters];
+    $out_lines = [];
     if (is_string($filters)) {
         $filters = [$filters];
     }