console-server: Call ringbuffer_fini() to mitigate leak report

Running obmc-console-server under valgrind yields:

```
==256429== 131,112 bytes in 1 blocks are definitely lost in loss record 2 of 2
==256429==    at 0x48407B4: malloc (vg_replace_malloc.c:381)
==256429==    by 0x10F3FC: ringbuffer_init (ringbuffer.c:33)
==256429==    by 0x10E61E: main (console-server.c:984)
```

Add the missing call to ringbuffer_fini() in the exit path.

Change-Id: I39b9a652a0565de73446f5ec7bfeac4bbc2281d8
Signed-off-by: Andrew Jeffery <andrew@codeconstruct.com.au>
diff --git a/console-server.c b/console-server.c
index d71c63a..83f7e50 100644
--- a/console-server.c
+++ b/console-server.c
@@ -982,17 +982,21 @@
 		}
 	}
 	console->rb = ringbuffer_init(buffer_size);
+	if (!console->rb) {
+		rc = -1;
+		goto out_config_fini;
+	}
 
 	if (set_socket_info(console, config, console_id)) {
 		rc = -1;
-		goto out_config_fini;
+		goto out_ringbuffer_fini;
 	}
 
 	uart_routing_init(config);
 
 	rc = tty_init(console, config, config_tty_kname);
 	if (rc) {
-		goto out_config_fini;
+		goto out_ringbuffer_fini;
 	}
 
 	dbus_init(console, config);
@@ -1005,6 +1009,9 @@
 
 	tty_fini(console);
 
+out_ringbuffer_fini:
+	ringbuffer_fini(console->rb);
+
 out_config_fini:
 	config_fini(config);