fixing the leak introduced in r69304

tests/test_build_ext.py

 import sys
 import os
-import tempfile
 import shutil
 from StringIO import StringIO
 
@@ -19,7 +18,8 @@ class BuildExtTestCase(unittest.TestCase):
     def setUp(self):
         # Create a simple test environment
         # Note that we're making changes to sys.path
-        self.tmp_dir = tempfile.mkdtemp(prefix="pythontest_")
+        self.tmp_dir = os.path.join(os.path.dirname(__file__), 'xx')
+        os.mkdir(self.tmp_dir)
         self.sys_path = sys.path[:]
         sys.path.append(self.tmp_dir)
         shutil.copy(_get_source_filename(), self.tmp_dir)