obs-outputs: Enable logging before calling RTMP_Init

Errors or warnings in RTMP_Init were not copied to the OBS log file
if they occured before the callback was set.

plugins/obs-outputs/rtmp-stream.c

@@ -145,8 +145,8 @@ static void *rtmp_stream_create(obs_data_t *settings, obs_output_t *output)
 	stream->output = output;
 	pthread_mutex_init_value(&stream->packets_mutex);
 
-	RTMP_Init(&stream->rtmp);
 	RTMP_LogSetCallback(log_rtmp);
+	RTMP_Init(&stream->rtmp);
 	RTMP_LogSetLevel(RTMP_LOGWARNING);
 
 	if (pthread_mutex_init(&stream->packets_mutex, NULL) != 0)