initctl: extend semantics for enable/disable cmd
initctl: extend semantics for enable/disable cmd

A system may, or may not, have the available/ and enabled/
subdirectories in /etc/finit.d.  This is up to distros but
we support the following, example uses /etc/finit.d as the
FINIT_RCSD base directory:

 1. No subdirectories
    - enable: nop
    - disable: nop
 2. Only available/
    - enable: checks if there's a service in available/
      then symlinks to /etc/finit.d/
    - disable: checks if service in /etc/finit.d is a
      symlink, then removes it
 3. Both available/ and enabled/
    - enable: relative symlink in enabled/ is created if
      service is available in available/
    - disable: symlink in enabled/ is removed if exists

Signed-off-by: Joachim Wiberg <583c295fd7602c168ad814279bbc3894ba65f5d6@gmail.com>

troglobit/finit,troglobit/finit