--- a/hgext/keyword.py	Wed Jan 14 20:29:47 2015 -0800
+++ b/hgext/keyword.py	Thu Jan 15 23:17:12 2015 +0100
@@ -411,7 +411,7 @@
         if args:
             # simulate hgrc parsing
             rcmaps = ['[keywordmaps]\n'] + [a + '\n' for a in args]
-            fp = repo.opener('hgrc', 'w')
+            fp = repo.vfs('hgrc', 'w')
             fp.writelines(rcmaps)
             fp.close()
             ui.readconfig(repo.join('hgrc'))