Revert "Set MultiROM version in header of new boot image"

Not needed anymore -> https://gerrit.omnirom.org/#/c/9623/

Just flash the recovery.img to FOTA (with the header set).

Example:

IMG=out/target/product/yuga/recovery.img
BASE=out/target/product/yuga/

RECOVERY_SUBVER="00"
DEST_NAME="TWRP_multirom_$PRODUCT_$(date +%Y%m%d)-$RECOVERY_SUBVER.img"

bbootimg -u $IMG -c "name = mrom$(date +%Y%m%d)-$RECOVERY_SUBVER"
cp $IMG $BASE$DEST_NAME

This reverts commit bf2bd471331337791188322034b76a6c7dc567bb.