bug#19536: [PATCH] package-upload-buffer-internal fails for tar files

[Kelly Dean]

It creates a file with a ⌜.tar⌝ extension that isn't a valid tar file.

Since elpa.gnu.org _does_ have valid tar files, I guess somebody wrote a script 
to work around this bug by overwriting the invalid tar files with the originals.

I'm submitting a patch for this since it affects validation of my patch for bug 
#19479, and I'm submitting the latter patch because it fixes a security 
vulnerability.

--- emacs-24.4/lisp/emacs-lisp/package-x.el
+++ emacs-24.4/lisp/emacs-lisp/package-x.el
@@ -243,7 +243,7 @@
                             (concat (symbol-name pkg-name) "-readme.txt")
                             package-archive-upload-base)))
 
-           (set-buffer pkg-buffer)
+           (set-buffer (if (eq file-type 'tar) tar-data-buffer pkg-buffer))
            (write-region (point-min) (point-max)
                          (expand-file-name
                           (format "%s-%s.%s" pkg-name pkg-version extension)