Cannot save revocation document

When I try to save my revocation document, I got questionned about my salt/password, and then a popup opens to "Save the file" and Sakia crashes:

/opt/sakia/libstdc++.so.6: version `GLIBCXX_3.4.20' not found (required by /usr/lib/x86_64-linux-gnu/libproxy.so.1)
Failed to load module: /usr/lib/x86_64-linux-gnu/gio/modules/libgiolibproxy.so

(sakia:5391): Gtk-WARNING **: Invalid input string

(sakia:5391): Gtk-WARNING **: Invalid input string
Erreur de segmentation (core dumped)

OS: Ubuntu 16.04 + Gnome

I will have to crowdfund in Ğ1 the integration of vagrant builds of Sakia ! The travis builds are getting more annoying everyday...

Duplicate of https://github.com/duniter/sakia/issues/712