You are right that we don't "preserve" the actual setting, but rather "preserve" the use of AoE for EBS if you are upgrading instead of forcing you to switch to iSCSI, which is the default for a fresh 2.0 installation. That `sed` statement, which is only executed if you are upgrading, essentially changes the 2.0 default back to 1.6.2 default.
You are right that we don't "preserve" the actual setting, but rather "preserve" the use of AoE for EBS if you are upgrading instead of forcing you to switch to iSCSI, which is the default for a fresh 2.0 installation. That `sed` statement, which is only executed if you are upgrading, essentially changes the 2.0 default back to 1.6.2 default.