classes/openwrt-services: Ensure rc.d exists
classes/openwrt-services: Ensure rc.d exists

Enabling procd scripts without /etc/rc.d won't work, so
make sure it exists.

Signed-off-by: Daniel F. Dickinson <8387375b7066459d9b5dcfebff567b1a650a8a0a@thecshore.com>

kraj/meta-openwrt