Update uninstall script.

Update uninstall script.

With this changeset the uninstall script should be a lot more
robust. "sub-packages" are handled, directories are only removed if they
are empty, and something more proactive is done about setuid files.

	* usr/lib/pkgusr/uninstall_package (usage): Reword it, taking into
	account needing pkgname arg.
	(check_suid): New.
	(dry_run): Use it.
	(run): Ditto.
	Handle empty directories more intelligently.
	Don't wipe out the .project file if uninstalling a "sub-pkg".

Signed-off-by: Steve Youngs <steve@steveyoungs.com>