emacs: Unbreak notmuch-show-rewind (the function to which Backspace is bound)

Commit 095a02211e696434e5b41a85ab516b3a639f9a9b broke the backspace
key by trying to execute nil as a function, (which obviously won't
work), when it was intended as a return value. Fix this now, (and pine
for a test suite that exercises the emacs user-interface of notmuch).

diff --git a/notmuch.el b/notmuch.el
index 5577dde797b6a6462fef23ae7c37c1845051f802..cd4d9963fb98c44a7b017faaf85391b24b293649 100644 (file)
--- a/notmuch.el
+++ b/notmuch.el
@@ -592,7 +592,7 @@ Returns nil if already on the first message in the buffer."
              nil
            t))
       (recenter 0)
-      (nil))))
+      nil)))
 
 (defun notmuch-show-previous-message ()
   "Backup to the previous message (whether open or closed)