client: Clarify D-Bus disconnected prompt

Make it clear that bluetoothctl is waiting to connect to bluetoothd
instead of showing something that looks like a prompt but which
doesn't accept any input.
diff --git a/client/main.c b/client/main.c
index 04be482..32341ad 100644
--- a/client/main.c
+++ b/client/main.c
@@ -50,7 +50,7 @@
 #define COLORED_DEL	COLOR_RED "DEL" COLOR_OFF
 
 #define PROMPT_ON	COLOR_BLUE "[bluetooth]" COLOR_OFF "# "
-#define PROMPT_OFF	"[bluetooth]# "
+#define PROMPT_OFF	"Waiting to connect to bluetoothd..."
 
 static GMainLoop *main_loop;
 static DBusConnection *dbus_conn;