dirstate: Remove unused variable

This fixes test-check-pyflakes.t which is currently failing
on the default branch.

Differential Revision: https://phab.mercurial-scm.org/D11658

mercurial/dirstateutils/v2.py

@@ -149,7 +149,6 b' class Node(object):'
         else:
             # There are no mtime-cached directories in the Python implementation
             flags = 0
-            mode = 0
             size = 0
             mtime_s = 0
             mtime_ns = 0