[libgnome-volume-control] Fix printf without supplied argument

[Robert Ancell <rancell src gnome org>]

commit 9f671ca77b3ef4b219aae77e21b034afc8e8a1b4
Author: Robert Ancell <robert ancell canonical com>
Date:   Wed Dec 6 13:45:58 2017 +1300

    Fix printf without supplied argument

 test-audio-device-selection.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/test-audio-device-selection.c b/test-audio-device-selection.c
index 294c0f7..b276a8c 100644
--- a/test-audio-device-selection.c
+++ b/test-audio-device-selection.c
@@ -41,7 +41,7 @@ audio_selection_needed (GvcMixerControl      *volume,
        args[n] = NULL;
 
        g_print ("+++ Audio selection needed for id %d\n", id);
-       g_print ("    Choices are: %s\n");
+       g_print ("    Choices are:\n");
        for (i = 0; args[i] != NULL; i++)
                g_print ("    %d. %s\n", i + 1, args[i]);