Log Message:
Updated notmuch to 0.23.2.

Notmuch 0.23.2 (2016-11-20)
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Emacs
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Fix notmuch-interesting-buffer and notmuch-cycle-notmuch-buffers.

  notmuch-tree-mode and notmuch-message-mode buffers are now
  considered interesting by `notmuch-interesting-buffer` and
  `notmuch-cycle-notmuch-buffers`.

Restore compatibility with Emacs 23.

  Notmuch support for Emacs 23 is now deprecated.