net: Fix TLS cert validation not being done for any network call
net: Fix TLS cert validation not being done for any network call

The default SoupSessionAsync behaviour does not perform any TLS certificate
validation, unless the ssl-use-system-ca-file property is set to true.

See https://blogs.gnome.org/mcatanzaro/2021/05/25/reminder-soupsessionsync-and-soupsessionasync-default-to-no-tls-certificate-verification/

This mitigates CVE-2016-20011.

Closes: #146

GNOME/grilo,GNOME/grilo