update-rc.d.bbclass: explicitly dep on initscripts

update-rc.d.bbclass: explicitly dep on initscripts

update-rc.d doesn't just want an initscripts package, it wants
initscripts-functions. In the case where VIRTUAL-RUNTIME_initscripts is set to
nothing, update-rc.d still needs initscripts-functions to satisfy its runtime
dependencies. Further, we shouldn't be using a *runtime* virtual in a *build
time* variable. This should resolve image creation failures with
configurations without sysv initscripts when a recipe inherits update-rc.d and
doesn't inherit systemd.

(From OE-Core rev: e6642ae0849e5ac3174c643a7693af25d829d6d1)

Signed-off-by: Christopher Larson <chris_larson@mentor.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>