XDG init -- Git rid of hack in site-start.el

XDG init -- Git rid of hack in site-start.el

It was wrong to use site-start.el to cope with a dynamic user init
directory.  This changeset puts it all into startup.el and removes the
site-start.el file.  Admins can breath a sigh of relief. :)

user-init-directory and lisp-initd-dir will now also be included in the
debugging output when using -debug-paths.

	* lisp/Makefile.am (corelispels): Remove site-start.el

	* lisp/site-start.el: Removed.

	* lisp/startup.el (find-user-init-directory): Actually set
	user-init-directory.
	Warn if multiple init directories were found.
	(forced-user-init-directory): New, non-nil when the
	user-init-directory has been set explicitly via the command
	line. NOT a user variable, keep ya grubby paws offit.
	(command-line-early): Ensure that all paths are correct when using
	"-u", "-user", "-user-init-directory", and inlude
	user-init-directory and lisp-initd-dir with -debug-paths.
	(startup-setup-paths): Use #'find-user-init-directory to maybe
	find the user's init directory.  Include user-init-directory, and
	lisp-initd-dir in debug output when -debug-paths.

Signed-off-by: Steve Youngs <steve@sxemacs.org>