overlay/15fcos: ensure valid aleph file

Due to an ordering mishap, some builds have both a `version` and a
`build` field. This causes bootupctl to fail while parsing the file.

Detect this case, and fix the aleph if necessary by removing the `build`
field.

This should be removed after the next barrier release.

Fixes: coreos/fedora-coreos-tracker#1724

overlay.d/15fcos/usr/lib/systemd/system-preset/45-fcos.preset

@@ -6,3 +6,6 @@ enable fwupd-refresh.timer
 # Check if wifi firmwares are missing when NetworkManager-wifi is installed
 # https://github.com/coreos/fedora-coreos-tracker/issues/1575
 enable coreos-check-wireless-firmwares.service
+# Strip extraneous field in aleph files to avoid bootupctl failing
+# https://github.com/coreos/fedora-coreos-tracker/issues/1724
+enable coreos-fix-aleph-file.service

overlay.d/15fcos/usr/lib/systemd/system/coreos-fix-aleph-file.service

@@ -0,0 +1,14 @@
+# Remove after the next barrier release
+
+[Unit]
+Description=Fix CoreOS Aleph File
+Documentation=https://github.com/coreos/fedora-coreos-tracker/issues/1724
+
+[Service]
+Type=oneshot
+ExecStart=/usr/libexec/coreos-fix-aleph-file
+RemainAfterExit=yes
+MountFlags=slave
+
+[Install]
+WantedBy=multi-user.target

overlay.d/15fcos/usr/libexec/coreos-fix-aleph-file

@@ -0,0 +1,28 @@
+#!/usr/bin/bash
+
+# This script removes the extra `version` field
+# which was shipped in a couple of builds
+# when switching to the `build` field
+# To be removed after the next barrier release.
+# see https://github.com/coreos/fedora-coreos-tracker/issues/1724 for more details
+
+set -euo pipefail
+
+ALEPH_FILE=/sysroot/.coreos-aleph-version.json
+
+if ! jq -e 'has("build") and has("version")' ${ALEPH_FILE}; then
+    echo "Aleph file does not require fixing"
+    exit
+fi
+
+echo "Aleph file is invalid; fixing"
+
+# remount /sysroot as writable
+mount -o rw,remount /sysroot
+
+# remove field "build"
+fixed_aleph=$(jq 'del(.build)' ${ALEPH_FILE})
+
+echo "$fixed_aleph" > ${ALEPH_FILE}
+
+echo "Aleph file is fixed"