install: fix: do not mark target slot with parent as non-bootable
install: fix: do not mark target slot with parent as non-bootable

* A target slot with a parent would not be used to boot, thus
  there will be no entry in the bootloader for it

Signed-off-by: Enrico Jorns <a2e5f936c390f36494e46e71bcfbe365bb1e8c49@pengutronix.de>

jluebbe/rauc,ejoerns/rauc,ejoerns/rauc,rauc/rauc,rauc/rauc,rauc/rauc,ejoerns/rauc,jluebbe/rauc,jluebbe/rauc