emacs-lisp/package.el: Don't overwrite downloads-in-progress.

lisp/ChangeLog

+2015-04-04  Artur Malabarba  <bruce.connor.am@gmail.com>
+
+	* emacs-lisp/package.el (package--download-and-read-archives): Add
+	`package-archives' to `package--downloads-in-progress' instead of
+	overwriting it.
+
 2015-04-04  Michael Albinus  <michael.albinus@gmx.de>
 
 	* net/tramp-cache.el (tramp-flush-directory-property): Quote directory

lisp/emacs-lisp/package.el

@@ -1410,7 +1410,9 @@ This populates `package-archive-contents'.  If ASYNC is non-nil,
 perform the downloads asynchronously."
   ;; The downloaded archive contents will be read as part of
   ;; `package--update-downloads-in-progress'.
-  (setq package--downloads-in-progress package-archives)
+  (setq package--downloads-in-progress
+        (append package-archives
+                package--downloads-in-progress))
   (dolist (archive package-archives)
     (condition-case-unless-debug nil
         (package--download-one-archive archive "archive-contents" async)