[GNC] Flatpak updates

[Chris Graves]

Geert,

Thanks for your work on this.

On Fedora 29, I installed maint-C3.8b-151-g555a467ab-D3.8b-13-g93566dc.

I get a Gnucash crash with nothing in the tracefile, but the following on
console:
Gtk-Message: 10:35:23.144: Failed to load module "pk-gtk-module"
Gtk-Message: 10:35:23.164: Failed to load module "pk-gtk-module"
gnucash: buffer.c:275: GWEN_Buffer_GetUsedBytes: Assertion `bf' failed.

The crash happens when running the AqB setup wizard.  The user has been
created, however when I edit the user and click Bank Settings->Retrieve
Account List, enter password, click Ok - boom, crash.

Chris