Reinstate p11-kit module configuration
Commit 5d8326ea removed gnome-keyring.module, which has broken pinning certificates using GCR for the common case, including basically all Geary users that use self-signed or other certs that don't have CAs available in the system store. Without this, GNOME apps don't have any means of securely storing certificates for pinning without rolling their own store (like EDS), requiring manual user intervention (like Midori), or assuming users have the technical knowledge to install and configure something like SoftSM (no one does).
To unbreak Geary, I'm currently looking at writing a custom GTlsDatabase impl that replaces current use of GCR and simply writes pinned certs to disk under ~, but it would be nice to not to have to do that, given that this used to Just Work.