bug#17693: 24.3.91.1; desktop-save-mode disables option -nw

[Stefan Guath]

VERSION:
GNU Emacs 24.3.91.1 (x86_64-apple-darwin13.2.0, NS apple-appkit-1265.20) of 
2014-05-23 on angelofdeaths-MacBook-Air.local

TO REPRODUCE BUG:

In OS X 10.9.3:
1) Create a .emacs file with only one expression:
    (desktop-save-mode)
2) Start emacs in graphical mode (i.e. double-click on Emacs.app icon).
3) Quit emacs, and answer "y" on question "Save desktop? (y or n)". The file 
.emacs.desktop is now created.
4) Run 'emacs -nw' in terminal.
5) Despite the '-nw' option, Emacs is now opened in graphical mode in a new 
non-terminal window.