bug#15495: loading packages shows: void-function cl--do-remf

[Darren Hoo]

steps to reproduce:

emacs -Q

M-x toggle-debug-on-error

M-x list-packages  brings the stacktrace:

Debugger entered--Lisp error: (void-function cl--do-remf)
  cl--do-remf(nil :kind)
  package-desc-from-define("caml" "3.12.0.1" "OCaml code editing
commands for Emacs" (quote nil))
  apply(package-desc-from-define ("caml" "3.12.0.1" "OCaml code
editing commands for Emacs" (quote nil)))
  package-process-define-package((define-package "caml" "3.12.0.1"
"OCaml code editing commands for Emacs" (quote nil))
"/Users/darren/.emacs.d/elpa/caml-3.12.0.1/caml-pkg.el")
  package-load-descriptor("/Users/darren/.emacs.d/elpa/caml-3.12.0.1")
  package-load-all-descriptors()
  package-initialize(t)
  list-packages(nil)
  call-interactively(list-packages record nil)
  command-execute(list-packages record)
  execute-extended-command(nil "list-packages")
  call-interactively(execute-extended-command nil nil)
  command-execute(execute-extended-command)

It seems that cl--do-remf is not autoloaded, have to explicitly require 'cl.