Add sysvinit PACKAGECONFIG which disables all sysvinit handling in
systemd if it isn't present.
Consolidate sysvinit handling so that when it's disabled we exclude all
sysvinit features.
(From OE-Core rev: 39ece7b3e604c9dfa046841e099e2a47b713f62c)
Signed-off-by: Alex Kiernan <alex.kiernan@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>