use original passphrase function instead of default one

gistfile1.diff

diff -r 3139b3d6d41d twittering-mode.el
--- a/twittering-mode.el        Sun Jun 26 23:37:23 2011 +0900
+++ b/twittering-mode.el        Sun Jul 10 15:07:52 2011 +0900
@@ -2798,7 +2798,7 @@
    ((require 'epa nil t)
     (let ((context (epg-make-context epa-protocol)))
       (epg-context-set-passphrase-callback
-       context #'epa-passphrase-callback-function)
+       context #'my-passphrase)
       (epg-context-set-progress-callback
        context
        (cons #'epa-progress-callback-function