Default the inventory_base_uri to the current directory

Signed-off-by: martin f. krafft <madduck@madduck.net>
diff --git a/config.py b/config.py
index e78c552..a19f834 100644
--- a/config.py
+++ b/config.py
@@ -92,12 +92,15 @@
         # if inventory_base is given, default to subdirectories
         nodes_uri = nodes_uri or 'nodes'
         classes_uri = classes_uri or 'classes'
-        # and prepend the inventory_base_uri
-        def _path_mangler_inner(path):
-            ret = os.path.join(inventory_base_uri, path)
-            ret = os.path.expanduser(ret)
-            return os.path.abspath(ret)
 
-        return map(_path_mangler_inner, (nodes_uri, classes_uri))
+    else:
+        inventory_base_uri = os.getcwd()
+
+    def _path_mangler_inner(path):
+        ret = os.path.join(inventory_base_uri, path)
+        ret = os.path.expanduser(ret)
+        return os.path.abspath(ret)
+
+    return map(_path_mangler_inner, (nodes_uri, classes_uri))
 
     return nodes_uri, classes_uri