[library-web] do not look for stale versions in directories that do not event exist

[Frederic Peters <fpeters src gnome org>]

commit c8cea2ac748bb5972aacdfb6ff1d592ba82ad147
Author: Frédéric Péters <fpeters 0d be>
Date:   Sat Sep 6 10:43:21 2014 +0200

    do not look for stale versions in directories that do not event exist

 src/document.py |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/src/document.py b/src/document.py
index c6d6932..33c4876 100644
--- a/src/document.py
+++ b/src/document.py
@@ -170,6 +170,8 @@ class Document:
             'channel': self.channel,
             'module': self.module }
         dirname = os.path.join(app.config.output_dir, base_path[1:])
+        if not os.path.exists(dirname):
+            return
         for filename in os.listdir(dirname):
             if filename.startswith('index.html'):
                 continue