use new ro.loki_disabled for unified variants not needing loki

This way, we only need to set the ENABLE_LOKI flag to have a loki enabled recovery
No more need to set an extra ro.loki_enabled property
Only modification needed now is for jflte variants not using loki
Only jflteatt and jfltevzw do
We have to set ro.loki_disabled to 1 for all other variants in libinit_jflte
6.25.4