Tidy base image by removing /var/log files

diskimage-builder/elements/base/cleanup.d/99-tidy-logs added
to tidy up (remove) initial logs files on disk images.

Makes for slightly smaller images, and easier times tracing post
boot issues.

Change-Id: Iee98b5d818e080bcd9635482bc29349a71938087

elements/base/cleanup.d/99-tidy-logs

@@ -0,0 +1,27 @@
+#!/bin/bash
+#
+# Copyright 2014 Hewlett-Packard Development Company, L.P.
+# All Rights Reserved.
+#
+# 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.
+#
+
+set -eux
+set -o pipefail
+
+# Truncate /var/log files in preparation for first boot
+sudo find $TARGET_ROOT/var/log -type f -delete
+
+# also /root logs
+sudo find $TARGET_ROOT/root -name \*.log -type f -delete
+