[PATCH 1 of 5 in crew] worker: add missing import of errno

[Bryan O'Sullivan]

# HG changeset patch
# User Bryan O'Sullivan <bryano at fb.com>
# Date 1365812197 25200
#      Fri Apr 12 17:16:37 2013 -0700
# Node ID 05d5821e0dc85bff757e6bace3e7978b6d0f2aef
# Parent  79580b3140cd7376c16395236ca24f36d2baa99c
worker: add missing import of errno

Found using Cython.

diff --git a/mercurial/worker.py b/mercurial/worker.py
--- a/mercurial/worker.py
+++ b/mercurial/worker.py
@@ -6,7 +6,7 @@
 # GNU General Public License version 2 or any later version.
 
 from i18n import _
-import os, signal, sys, threading, util
+import errno, os, signal, sys, threading, util
 
 def countcpus():
     '''try to count the number of CPUs on the system'''