fixes broken webarchive test case, a=chris

diff --git a/tests/web_archive_test.php b/tests/web_archive_test.php
index 43867df5f..b68b6d200 100755
--- a/tests/web_archive_test.php
+++ b/tests/web_archive_test.php
@@ -43,7 +43,7 @@ require_once BASE_DIR."/lib/web_archive.php";
  *  A compressor determines how objects are written into a web_archive.
  *  This require loads a gzip-based compressor.
  */
-require_once BASE_DIR."/lib/gzip_compressor.php";
+require_once BASE_DIR."/lib/compressors/gzip_compressor.php";

 /**
  * UnitTest for the WebArchive class. A web archive is used to store