debian-minimal: Set bullseye version

Currently Debian sets /etc/debian_version to "bullseye/sid" and, due
to a series of issues explained in [1] more fully "lsb_release -c" in
the OpenDev environment doesn't return the distribution code name.
Overriding this to the final release version fixes this.

[1] http://lists.opendev.org/pipermail/service-discuss/2021-April/000222.html

Change-Id: I00c1741dac6ad5f2c4bf855a207f17d8985bc763

diskimage_builder/elements/debootstrap/cleanup.d/99-set-bullseye-version

@@ -0,0 +1,23 @@
+#!/bin/bash
+#
+# Copyright 2021 Red Hat, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+#
+if [ ${DIB_DEBUG_TRACE:-1} -gt 0 ]; then
+    set -x
+fi
+set -eu
+set -o pipefail
+
+sudo sed -i 's,bullseye/sid,11.0,' $TARGET_ROOT/etc/debian_version