Fix the gzip.at test case.

* tests/gzip.at: Suppress gzip error output, as it can differ
depending on its version etc. Bug reported by Ludovic Courtès.

tests/gzip.at

@@ -1,7 +1,7 @@
 # Process this file with autom4te to create testsuite. -*- Autotest -*-
 
 # Test suite for GNU tar.
-# Copyright (C) 2004, 2007, 2009 Free Software Foundation, Inc.
+# Copyright (C) 2004, 2007, 2009, 2010 Free Software Foundation, Inc.
 
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -27,13 +27,14 @@ unset TAR_OPTIONS
 
 AT_CHECK([
 AT_GZIP_PREREQ
-tar xfvz /dev/null
+tar xfvz /dev/null 2>err
+RC=$?
+sed -n '/^tar:/p' err >&2
+exit $RC
 ],
 [2],
 [],
-[
-gzip: stdin: unexpected end of file
-tar: Child returned status 1
+[tar: Child returned status 1
 tar: Error is not recoverable: exiting now
 ],
 [],[])