[rygel/rygel-0-22] media-export: Fix album art for m4a files

[Jens Georg <jensgeorg src gnome org>]

commit d779ef635de904604941ea98e29f0eee2f7ebd6b
Author: Jens Georg <mail jensge org>
Date:   Sun Jun 15 11:51:22 2014 +0200

    media-export: Fix album art for m4a files
    
    The tag is PREVIEW_IMAGE in that case, not IMAGE
    
    Signed-off-by: Jens Georg <mail jensge org>
    
    Conflicts:
        src/plugins/media-export/rygel-media-export-item-factory.vala

 .../rygel-media-export-item-factory.vala           |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/src/plugins/media-export/rygel-media-export-item-factory.vala 
b/src/plugins/media-export/rygel-media-export-item-factory.vala
index 14296b9..e52277f 100644
--- a/src/plugins/media-export/rygel-media-export-item-factory.vala
+++ b/src/plugins/media-export/rygel-media-export-item-factory.vala
@@ -271,6 +271,10 @@ namespace Rygel.MediaExport.ItemFactory {
         Sample sample;
         tags.get_sample (Tags.IMAGE, out sample);
         if (sample == null) {
+            tags.get_sample (Tags.PREVIEW_IMAGE, out sample);
+        }
+
+        if (sample == null) {
             return item;
         }
         unowned Structure structure = sample.get_caps ().get_structure (0);