Deprecate bsddb for removal in Python 3.0.

Closes issue 3776.
Review by Nick Coghlan.
diff --git a/Doc/library/bsddb.rst b/Doc/library/bsddb.rst
index ed45619..52ff38a 100644
--- a/Doc/library/bsddb.rst
+++ b/Doc/library/bsddb.rst
@@ -6,6 +6,9 @@
    :synopsis: Interface to Berkeley DB database library
 .. sectionauthor:: Skip Montanaro <skip@pobox.com>
 
+.. deprecated:: 2.6
+    The :mod:`bsddb` module has been deprecated for removal in Python 3.0.
+
 
 The :mod:`bsddb` module provides an interface to the Berkeley DB library.  Users
 can create hash, btree or record based library files using the appropriate open