[rygel] renderer: Accept missing mime type in AVTransport.is_playlist()

[Jens Georg <jensgeorg src gnome org>]

commit dbcd8aef606ef343b37f4be659d6df32462089fa
Author: Jussi Kukkonen <jussi kukkonen intel com>
Date:   Fri Nov 8 15:24:47 2013 +0200

    renderer: Accept missing mime type in AVTransport.is_playlist()
    
    "assertion 'mime != NULL' failed" is not useful here.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=711661

 src/librygel-renderer/rygel-av-transport.vala |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/librygel-renderer/rygel-av-transport.vala b/src/librygel-renderer/rygel-av-transport.vala
index 7d38e9a..d534d91 100644
--- a/src/librygel-renderer/rygel-av-transport.vala
+++ b/src/librygel-renderer/rygel-av-transport.vala
@@ -736,7 +736,7 @@ internal class Rygel.AVTransport : Service {
         return result;
     }
 
-    private bool is_playlist (string mime, string? features) {
+    private bool is_playlist (string? mime, string? features) {
         return mime == "text/xml" && features != null &&
                features.has_prefix ("DLNA.ORG_PN=DIDL_S");
     }