gvariant-text: fix bytestring example
ord('a') == 97 == 0x61 != 0x97.
>>> GLib.Variant.parse(None, "[byte 0x97, 0x98, 0x99, 0]", None, None)
GLib.Variant('ay', b'\227\230\231')
>>> GLib.Variant.parse(None, "[byte 0x61, 0x62, 0x63, 0]", None, None)
GLib.Variant('ay', b'abc')
Edited by Will Thompson