rauc: ensure RAUC state directory exists

RAUC uses a state file `status.raucs`. In the Oniro images this file is
prescribed to be in `/run/mount/sysdata/common/`. Exploratory testing
has found that RAUC cannot create the leading directory automatically
and fails to handle an update transaction.

Resolve this by adding a systemd configuration override file which
creates the directory using ExecStartPre=

Closes: https://git.ostc-eu.org/distro/oniro/-/issues/158


Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@huawei.com>

meta-oniro-core/recipes-core/rauc/files/rauc-state-dir.conf

+# SPDX-FileCopyrightText: Huawei Inc.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+# Create directory where RAUC stores the status file. This must be
+# synchronized with the system.conf file installed into /etc/rauc/system.conf.
+[Service]
+ExecStartPre=/bin/mkdir -p /run/mount/sysdata/common

meta-oniro-core/recipes-core/rauc/rauc_%.bbappend

@@ -43,3 +43,17 @@ do_install_append() {
         bbwarn "The image is using a known, insecure test key for verifying RAUC bundles. Do not use this in production systems."
     fi
 }
+
+# Install Oniro specific override for RAUC state directory.
+
+SRC_URI_append = " \
+  file://rauc-state-dir.conf \
+  "
+
+FILES_${PN}-service += "\
+	${systemd_unitdir}/system/rauc.service.d/*.conf \
+	"
+
+do_install_append() {
+    install -D -m 644 ${WORKDIR}/rauc-state-dir.conf --target-directory=${D}${systemd_unitdir}/system/rauc.service.d/
+}