Allow node to be None to trigger inventory

Signed-off-by: martin f. krafft <madduck@madduck.net>
diff --git a/reclass/__init__.py b/reclass/__init__.py
index 63492e6..58fa4ef 100644
--- a/reclass/__init__.py
+++ b/reclass/__init__.py
@@ -13,7 +13,7 @@
 def get_data(storage_type, nodes_uri, classes_uri, applications_postfix, node):
     storage_class = StorageBackendLoader(storage_type).load()
     storage = storage_class(nodes_uri, classes_uri, applications_postfix)
-    if node is False:
+    if not node:
         ret = storage.inventory()
     else:
         ret = storage.nodeinfo(node)