Don't mutilate keyword arguments in :bind

The parsing logic in `use-package-normalize-pairs' is not designed to
deal with keyword arguments. However, `use-package-normalize-pairs' is
used to process the arguments to :bind, which can include keyword
arguments. These keyword arguments are supposed to be passed untouched
to the underlying `bind-keys' function, but there is a clause in
`use-package-normalize-pairs' that replaces lists with their first
element. Thus an invocation like:

(use-package company
  :bind (:map company-active-map
         :filter (company-explicit-action-p)
         ("RET" . company-complete-selection)))

Generates code like this:

(bind-keys
  :map company-active-map
  :filter company-explicit-action-p
  ("RET" . company-complete-selection))

Which generates an error since `company-explicit-action-p' is now
being referenced as a variable rather than a function.

The proper solution is to refactor the logic that goes into parsing
uses of :bind, but this commit adds a temporary patch to eliminate the
above problem, while trying to be as reverse-compatible as possible.
In particular it just inhibits the list-to-first-element
transformation when the previous element processed was a keyword.

lisp/use-package/use-package.el

@@ -964,12 +964,15 @@ If RECURSED is non-nil, recurse into sublists."
    ((use-package-is-pair arg key-pred val-pred)
     (list arg))
    ((and (not recursed) (listp arg) (listp (cdr arg)))
-    (mapcar #'(lambda (x)
-                (let ((ret (use-package-normalize-pairs
-                            key-pred val-pred name label x t)))
-                  (if (listp ret)
-                      (car ret)
-                    ret))) arg))
+    (let ((last-item nil))
+      (mapcar #'(lambda (x)
+                  (prog1
+                      (let ((ret (use-package-normalize-pairs
+                                  key-pred val-pred name label x t)))
+                        (if (and (listp ret) (not (keywordp last-item)))
+                            (car ret)
+                          ret))
+                    (setq last-item x))) arg)))
    (t arg)))
 
 (defun use-package-normalize-binder (name keyword args)