fix an error message and make const correct

Sun Mar 04 16:28:52 2001  George Lebl <jirka@5z.com>

	* daemon/filecheck.[ch]: fix an error message and make const correct

	* gui/gdmlogin.c: make the photo checking code saner, this assumes
	  we're root and can read anyone's files, really and this is bad,
	  oh well, it is sort of weird.  Also a bunch of cleanup and
	  constization.

	* gui/Makefile.am: don't link to filecheck anymore

	* daemon/slave.c, gui/gdmlogin.c: cleanup some code, make GDM_QUIT
	  work for doing cleanup.  Make it not actually quit but just
	  cleanup to prepare to be killed.