[rygel/rygel-0-22] server: Prevent critical on upload

[Jens Georg <jensgeorg src gnome org>]

commit b9f0abbac416e1d8559b08f5ceecb5194c66724c
Author: Jens Georg <mail jensge org>
Date:   Sat Jun 14 22:30:30 2014 +0200

    server: Prevent critical on upload
    
    Signed-off-by: Jens Georg <mail jensge org>
    
    Conflicts:
        src/librygel-server/rygel-media-art-store.vala

 src/librygel-server/rygel-media-art-store.vala |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/src/librygel-server/rygel-media-art-store.vala b/src/librygel-server/rygel-media-art-store.vala
index 5160760..786ab04 100644
--- a/src/librygel-server/rygel-media-art-store.vala
+++ b/src/librygel-server/rygel-media-art-store.vala
@@ -67,7 +67,7 @@ public class Rygel.MediaArtStore : GLib.Object {
 
         foreach (var type in types) {
             file = this.get_media_art_file (type, item, simple);
-            if (file.query_exists (null)) {
+            if (file != null && file.query_exists (null)) {
                 break;
             } else {
                 file = null;
@@ -102,9 +102,9 @@ public class Rygel.MediaArtStore : GLib.Object {
         return thumb;
     }
 
-    public File get_media_art_file (string    type,
-                                    MusicItem item,
-                                    bool      simple = false) {
+    public File? get_media_art_file (string    type,
+                                     MusicItem item,
+                                     bool      simple = false) {
         string hash;
         string suffix;