1. If gnome_enable is not set, gdm_enable will remain undefined.
2. Change the order of calling load_rc_config() and setting the
default variables to the typical order for ports
3. Not only is the checkyesno for gdm_enable in gdm_start() not
needed, it causes problems if, for example the user does
'/usr/local/etc/rc.d/gdm onestart' from the command line.
4. Switch to using 'unlink' instead of 'rm -f'
5. If lshal does not exist, error out instead of looping
6. Mark a variable local
Bump the PORTREVISION.
PR: ports/159391
Submitted by: dougb
Feature safe: yes
