[pitivi] Fix a traceback dragging source list items on the source list itself.

[Edward Hervey <edwardrv src gnome org>]

commit d035473defa1948664938831a92cad4f7e39ead1
Author: Alessandro Decina <alessandro d gmail com>
Date:   Wed Aug 5 12:49:50 2009 +0200

    Fix a traceback dragging source list items on the source list itself.

 pitivi/ui/sourcelist.py |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)
---
diff --git a/pitivi/ui/sourcelist.py b/pitivi/ui/sourcelist.py
index dc10b76..b73b2f4 100644
--- a/pitivi/ui/sourcelist.py
+++ b/pitivi/ui/sourcelist.py
@@ -41,6 +41,7 @@ from pitivi.stream import VideoStream, AudioStream, TextStream, \
 from pitivi.settings import GlobalSettings
 from pitivi.utils import beautify_length
 from pitivi.log.loggable import Loggable
+from pitivi.sourcelist import SourceListError
 
 GlobalSettings.addConfigSection('clip-library')
 GlobalSettings.addConfigOption('lastImportFolder',
@@ -713,7 +714,11 @@ class SourceList(gtk.VBox, Loggable):
                 directories = [incoming]
         if directories:
             self.addFolders(directories)
-        self.addUris(filenames)
+        try:
+            self.addUris(filenames)
+        except SourceListError:
+            # filenames already present in the sourcelist
+            pass
 
     def _dndTreeBeginCb(self, unused_widget, context):
         self.info("tree drag_begin")