[rhythmbox] library: don't crash if we can't create an encoder

[Jonathan Matthew <jmatthew src gnome org>]

commit 2230f5ce5e7c889ececa1413148512a3f5b78d5e
Author: Jonathan Matthew <jonathan d14n org>
Date:   Sun Jul 7 23:14:45 2013 +1000

    library: don't crash if we can't create an encoder

 sources/rb-library-source.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/sources/rb-library-source.c b/sources/rb-library-source.c
index bbca1db..1afc971 100644
--- a/sources/rb-library-source.c
+++ b/sources/rb-library-source.c
@@ -657,7 +657,7 @@ update_property_editor_for_preset (RBLibrarySource *source, const char *media_ty
        }
 
        /* create new property editor, if required */
-       if (style != -1) {
+       if (style != -1 && source->priv->encoder_element) {
                GstEncodingProfile *profile;
                char **profile_settings;