issue #477: old Py zlib did not include extended exception text.

tests/first_stage_test.py

@@ -30,6 +30,7 @@ class CommandLineTest(testlib.RouterMixin, testlib.TestCase):
         # success.
 
         fp = open("/dev/null", "r")
+        try:
             proc = subprocess.Popen(args,
                 stdin=fp,
                 stdout=subprocess.PIPE,
@@ -38,7 +39,9 @@ class CommandLineTest(testlib.RouterMixin, testlib.TestCase):
             stdout, stderr = proc.communicate()
             self.assertEquals(0, proc.returncode)
             self.assertEquals(mitogen.parent.Stream.EC0_MARKER, stdout)
-        self.assertIn(b("Error -5 while decompressing data: incomplete or truncated stream"), stderr)
+            self.assertIn(b("Error -5 while decompressing data"), stderr)
+        finally:
+            fp.close()
 
 
 if __name__ == '__main__':