Do not add SSL session to the OpenSSL internal cache
requested to merge GomesGoncalo/glib-networking:goncalo.gomes/openssl-random-session-invalidated into master
When SSL session caching is handled externally, explicitly adding the SSL session to the OpenSSL internal session cache may cause the session to become unresumable. When attempting to reuse an unresumable session from the external cache, OpenSSL will automatically create a new one which results in a full handshake being performed.
This commit removes the explicit call to SSL_CTX_add_session() as the call to SSL_add_session() is sufficient to set a session resumable.