[pitivi] prefs: prefix regex string with 'r'

[Jean-François Fortin Tam <jfft src gnome org>]

commit 0402a363feccda89f5500fb201d865aadf92f06c
Author: Mathieu Duponchelle <mduponchelle1 gmail com>
Date:   Thu Dec 26 16:12:47 2013 +0100

    prefs: prefix regex string with 'r'

 pitivi/dialogs/prefs.py |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/pitivi/dialogs/prefs.py b/pitivi/dialogs/prefs.py
index 22df84b..0f1b9fa 100644
--- a/pitivi/dialogs/prefs.py
+++ b/pitivi/dialogs/prefs.py
@@ -447,7 +447,7 @@ if __name__ == "__main__":
         label="Numbers only",
         section="Test",
         description="This input validates its input with a regex",
-        matches="^-?\d+(\.\d+)?$")
+        matches=r"^-?\d+(\.\d+)?$")
 
 ## other
     PreferencesDialog.addPathPreference('aPathPreference',