[gnome-bluetooth] lib: Add guard for public killswitch function

[Bastien Nocera <hadess src gnome org>]

commit 55d675bf2c8a9125841562ac7add840b623f6a98
Author: Bastien Nocera <hadess hadess net>
Date:   Mon Jul 23 17:31:13 2012 +0100

    lib: Add guard for public killswitch function

 lib/bluetooth-killswitch.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/lib/bluetooth-killswitch.c b/lib/bluetooth-killswitch.c
index ae4761c..1c4f7d1 100644
--- a/lib/bluetooth-killswitch.c
+++ b/lib/bluetooth-killswitch.c
@@ -156,6 +156,7 @@ bluetooth_killswitch_set_state (BluetoothKillswitch *killswitch,
 	struct rfkill_event event;
 	ssize_t len;
 
+	g_return_if_fail (BLUETOOTH_IS_KILLSWITCH (killswitch));
 	g_return_if_fail (state != KILLSWITCH_STATE_HARD_BLOCKED);
 
 	priv = killswitch->priv;