The previously used GStreamer custom custom patch to load certificate
files from the CA_CERTIFICATES environment variable is no longer
effective with glib-networking 2.58 and instead API was added to the
upcoming glib 2.60 release (backported to glib 2.58 in GStreamer's
cerbero) to set the default TLS database.
This patch makes use of the new API to set the default TLS database
and behaves similarly as the previous CA_CERTIFICATES environment