Delete the function svc_get_all().

Delete the function svc_get_all().
In svc_is_avail(), this simplifies the code by getting rid of the loop.
When running "rcctl status", this allows to not run svc_is_special() -
which spawns a grep - for each and every service, resulting in a 20%
speedup.  As a bonus, we get the special services listed at the end,
where they are easier to see than mixed in with the daemons.
ok ajacoutot@ jasper@