buildroot

glib-networking: specify ca-certificates pathspec

Otherwise the configure script will probe the distro directories for it
and it may not match what we use, for example fedora uses /etc/pki
instead of /etc/ssl.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>