initrdscripts: abroot: add missing dependency

The abroot script sources balena-config-defaults so let's make sure
it's included in the build.

Change-type: patch
Signed-off-by: Alex Gonzalez <alexg@balena.io>

meta-balena-common/recipes-core/initrdscripts/initramfs-module-abroot_1.0.bb

@@ -15,4 +15,5 @@ do_install() {
     install -m 0755 ${WORKDIR}/abroot ${D}/init.d/73-abroot
 }
 
+RDEPENDS:${PN}:append = " balena-config-vars-config"
 FILES:${PN} = "/init.d/73-abroot"