Bug#656578: Can't install extensions from gnome site (exception in /usr/share/gnome-shell/js/ui/extensionSystem.js)

[Евгений 'Rush' Непомнящий]

i don't know this is a bug or a feature.

1. This bug happened when gnome -> network settings -> proxy set to
"manual", so if you set it to "none", all things will work as you
expect.
2. Developers don't check message status code in callback within
_httpSession.queue_message call, so when request failed we seeing this
useless error message in the log.

Hope this help you.