diff --git a/mercurial/thirdparty/concurrent/__init__.py b/mercurial/thirdparty/concurrent/__init__.py
--- a/mercurial/thirdparty/concurrent/__init__.py
+++ b/mercurial/thirdparty/concurrent/__init__.py
@@ -1,3 +0,0 @@
-from pkgutil import extend_path
-
-__path__ = extend_path(__path__, __name__)