Fix FetchUrl error notification regex, a=chris

diff --git a/src/library/FetchUrl.php b/src/library/FetchUrl.php
index 4f8a90343..7a8253c9d 100755
--- a/src/library/FetchUrl.php
+++ b/src/library/FetchUrl.php
@@ -934,7 +934,7 @@ class FetchUrl implements CrawlConstants
      */
     public static function checkResponseForErrors($response)
     {
-        if (preg_match("/NOTICE|WARNING|FATAL/i", $response)) {
+        if (preg_match("/\bNOTICE|WARNING|FATAL\b/i", $response)) {
             crawlLog("There appears to have been an error in the server ".
                 "response. Response was:");
             crawlLog(wordwrap($response));