repair: fix missing import

introduced by: b5c0c7d0f83fe56240ce7a919581f1cbff4f5ee5

mercurial/repair.py

@@ -10,6 +10,7 b' from mercurial import changegroup, bookm'
 from mercurial.node import short
 from mercurial.i18n import _
 import os
+import errno
 
 def _bundle(repo, bases, heads, node, suffix, compress=True):
     """create a bundle with the specified revisions as a backup"""