merging revision 74100 from trunk:
http://bugs.python.org/issue6499
gzip.GzipFile may not exist as a parent class
diff --git a/Lib/xmlrpc/client.py b/Lib/xmlrpc/client.py
index fc32925..549006b 100644
--- a/Lib/xmlrpc/client.py
+++ b/Lib/xmlrpc/client.py
@@ -1076,7 +1076,7 @@
 # @param response A stream supporting a read() method
 # @return a file-like object that the decoded data can be read() from
 
-class GzipDecodedResponse(gzip.GzipFile):
+class GzipDecodedResponse(gzip.GzipFile if gzip else object):
     """a file-like object to decode a response encoded with the gzip
     method, as described in RFC 1952.
     """