sysklogd: fix packaging issue

sysklogd inherits update-rc.d, but not from systemd.bbclass, so we need to
set INHIBIT_UPDATERCD_BBCLASS to "1" if 'sysvinit' is not in
DISTRO_FEATURES so that it does not add any un-necessary package
dependencies

http://jira.alm.mentorg.com:8080/browse/SB-3428

Signed-off-by: Fahad Usman <fahad_usman@mentor.com>