gnutls: set sysconfdir
gnutls: share CA file generated by openssl's post-install
Stop bottling glib-networking (for now)

This package installs files into the top-level gio modules directory,
thus the bottle only installs a bunch of locale files.
glib-networking: use CA file installed by gnutls/openssl

Goodbye curl-ca-bundle.
gnutls 3.2.13
gnutls: update 3.2.13 bottle.