Fix error in Emacs 24.3

bound-and-true-p is a macro which quotes its argument, so passing it a symbol results in this:

Debugger entered--Lisp error: (wrong-type-argument symbolp (quote desktop-save-mode))
  boundp((quote desktop-save-mode))
  frame-restore-desktop-restores-frame-p()
  frame-restore-initial-frame()
  run-hooks(after-init-hook)
  command-line()
  normal-top-level()
Merge pull request #2 from purcell/patch-2

Fix error in Emacs 24.3