fix db connection handling

contrib/src/web/faces.py

@@ -79,12 +79,13 @@ cleaner = FileCleaner()
 @app.before_request
 def before_request():
     g.db = database
+    if g.db.is_closed():
         g.db.connect()
 
-@app.after_request
-def after_request(response):
+@app.teardown_request
+def teardown_request(exc):
+    if not g.db.is_closed():
         g.db.close()
-    return response
 
 @app.route('/')
 def index():