[mhonarc] error log should be binary

[Olav Vitters <ovitters src gnome org>]

commit 1e52cf403c0f6db03970d10d71a1df83be3c5df5
Author: Olav Vitters <olav vitters nl>
Date:   Wed Feb 13 15:55:56 2013 +0100

    error log should be binary

 archive.py |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/archive.py b/archive.py
index 741d521..c68b3bb 100755
--- a/archive.py
+++ b/archive.py
@@ -97,7 +97,7 @@ class Archiver:
             rcfile = self.PRIVATE_RCFILE if self.private else self.PUBLIC_RCFILE
 
             # Call mhonarc for all messages in 'newmsgs'
-            with open(self.ERRORLOG, "a") as error_fd:
+            with open(self.ERRORLOG, "ab") as error_fd:
                 cmd = ['mhonarc', '-umask', '022', '-rcfile', rcfile, '-add', '-outdir', path, newmsgs.name,
                                   '-definevar', 'ARCHDATE=%s LISTNAME=%s' % (archivepath, self.listname)]