gzip file doesn't store old mtime and old filename

            # open file not done in GzipFile, to escape writing of filename

            # in gzip file. This change md5.

            fdest = open(dest, "wb")

            fdest = gzip.GzipFile(filename=os.path.basename(source),

                                  fileobj=fdest,

                                  mtime=os.stat(source).st_mtime)

            fdest = gzip.GzipFile(fileobj=fdest, filename="", mtime=0)

            fsource.consume(fdest)

            fsource.close()

            fdest.close()