Add vvv printf-debugging function to yaml_fs

Signed-off-by: martin f. krafft <madduck@madduck.net>
diff --git a/reclass/storage/yaml_fs/__init__.py b/reclass/storage/yaml_fs/__init__.py
index fb10dc0..d6f3cbd 100644
--- a/reclass/storage/yaml_fs/__init__.py
+++ b/reclass/storage/yaml_fs/__init__.py
@@ -6,7 +6,7 @@
 # Copyright © 2007–13 martin f. krafft <madduck@madduck.net>
 # Released under the terms of the Artistic Licence 2.0
 #
-import os
+import os, sys
 from reclass.storage import NodeStorageBase
 from yamlfile import YamlFile
 from directory import Directory
@@ -15,6 +15,10 @@
 
 FILE_EXTENSION = '.yml'
 
+def vvv(msg):
+    #print >>sys.stderr, msg
+    pass
+
 class ExternalNodeStorage(NodeStorageBase):
 
     def __init__(self, nodes_uri, classes_uri):
@@ -59,6 +63,7 @@
         entities = {}
 
         def register_fn(dirpath, filenames):
+            vvv('REGISTER {0} in path {1}'.format(filenames, dirpath))
             for f in filter(lambda f: f.endswith(FILE_EXTENSION), filenames):
                 name = f[:-len(FILE_EXTENSION)]
                 nodeinfo = self.nodeinfo(name)