[grilo] core: Improve warning message for non-handled related keys.

[Bastien Nocera <hadess src gnome org>]

commit 727e0c426cfbfee3163191520cb988c7cc7229a7
Author: Rafael Fonseca <r4f4rfs gmail com>
Date:   Thu Feb 4 15:10:36 2016 +0100

    core: Improve warning message for non-handled related keys.
    
    When setting a non-handled related key, Grilo complains with the following
    message
    
    Grilo-WARNING **: [data] data/grl-data.c:742: Trying to add an empty
        GrlRelatedKeys to GrlData
    
    This patch improves the error reporting a bit by saying which key type is not
    currently being handled.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=707643

 src/data/grl-related-keys.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/src/data/grl-related-keys.c b/src/data/grl-related-keys.c
index 3a03d54..04cb38e 100644
--- a/src/data/grl-related-keys.c
+++ b/src/data/grl-related-keys.c
@@ -159,6 +159,9 @@ grl_related_keys_new_valist (GrlKeyID key,
                                    next_key,
                                    next_value,
                                    va_arg (args, gsize));
+    } else {
+      GRL_WARNING ("related key type '%s' not handled",
+                   g_type_name (key_type));
     }
     next_key = va_arg (args, GrlKeyID);
   }