update-rc.d: Improve RRECOMMENDS handling

update-rc.d: Improve RRECOMMENDS handling

Unfortunately the combination of:

RRECOMMENDS_${PN} = "X"
UPDATERCPN = "${PN}"
RRECOMMENDS_${UPDATERCPN}_append = "Y"

is tricky for bitbake to order correctly since RRECOMMENDS_${UPDATERCPN} can
become "Y" which can then completely overwrite RRECOMMENDS_${PN}.

Avoid these issues and improve handling in general by explictly setting
the RRECOMMENDS on the list of packages modified in the general
code.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>