error upgrade extension

[ivano borsato <iacopodeenosee gmail com>]

Hi
I am having a problem updating an extension for GnomeShell 3.16.3, in
an attempt to update from extensions.gnome.org web site you get only
the cancellation of the extension's folder and after this it is no
longer possible to reinstall, without any error message in the log of
GnomeShell and also in the log of firefox, I do not understand what
the problem is ,is it in the extension or in the web site?
here are the reports:
https://github.com/iacopodeenosee/EasyScreenCast/issues/41

thx