[pitivi] previewers: if queue is emppty, _get_wish will return True, causing us to try to pop an empty queue.

[Thibault Saunier <tsaunier src gnome org>]

commit 182963b18e124dfaa6952f709d5da336ca118af8
Author: Mathieu Duponchelle <mathieu duponchelle epitech eu>
Date:   Thu Sep 26 03:40:40 2013 +0200

    previewers: if queue is emppty, _get_wish will return True, causing
    us to try to pop an empty queue.

 pitivi/timeline/previewers.py |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/pitivi/timeline/previewers.py b/pitivi/timeline/previewers.py
index bce9f73..8be06df 100644
--- a/pitivi/timeline/previewers.py
+++ b/pitivi/timeline/previewers.py
@@ -296,7 +296,7 @@ class VideoPreviewer(Clutter.ScrollActor, PreviewGenerator, Zoomable, Loggable):
         return False
 
     def _create_next_thumb(self):
-        if not self.wishlist:
+        if not self.wishlist or not self.queue:
             # nothing left to do
             self.debug("Thumbnails generation complete")
             self.stopGeneration()