The silent reconnect (GOAWAY) is supposed to be used for switching the
connection to a different server. As such, cleanly shutting down the
RTMP connection can destroy state that needs to be preserved in order
for the GOAWAY-enabled server to properly resume the same stream on
reconnect.
This commit closes the TLS/TCP connection before calling RTMP_Close,
causing librtmp to skip the FCUnpublish and deleteStream messages.