recent undo-tree commit and generated ~undo-tree~ files

[Joseph Mingrone]

Hello,

After commit 1f8d005409ceaa9ff27be04dabc155dcfd90fd03 to the elpa
repository, which updates undo-tree to 0.8.2, whenever closing a file, a
new file of the form <file>.~undo-tree~ is written to disk.  The
contents of the generated file are something like this.

(undo-tree-save-format-version . 1)
"7424f62f1237984237e1b27d050c613dcb2e6a01"
[nil nil nil nil (25137 27709 755877 763000) 0 nil]
([nil nil ((#(";" 0 1 (face font-lock-comment-delimiter-face fontified t)) . 1) 
(t 25137 26978 515241 0)) nil (25137 27709 755875 613000) 0 nil])
([nil current ((1 . 2)) nil (25137 27709 755869 986000) 0 nil])
nil

This is with a recent Emacs build from the master branch and default
undo-tree configuration.  Setting `undo-tree-auto-save-history' to nil
stops these files from being generated.  Perhaps this is new, intended
functionality, but it wasn't clear to me looking at the commit.

Regards,

Joe