Export die() function

I realised I'd been using die() in a few places assuming it was
available, but it wasn't exported.  I guess it didn't matter because
whatever was wrong, we were failing anyway :)

This exports the function to make it available to sub-processes, which
should remove the need to source it as done in several places.

Change-Id: I7b9a5a6db406e160099b6ed9fde80455ae227327

elements/base/extra-data.d/50-store-build-settings

@@ -7,7 +7,6 @@ fi
 set -eu
 set -o pipefail
 
-source $_LIB/die
 [ -n "$TMP_HOOKS_PATH" ] || die "Temp hook path not set"
 
 echo "$DIB_ENV" > $TMP_HOOKS_PATH/dib_environment

elements/local-config/extra-data.d/62-ssh-key

@@ -8,7 +8,6 @@ fi
 set -eu
 set -o pipefail
 
-source $_LIB/die
 [ -n "$TMP_HOOKS_PATH" ] || die "Temp hook path not set"
 
 if [ -e ~/.ssh/authorized_keys ]; then

elements/partitioning-sfdisk/block-device.d/10-partitioning-sfdisk

@@ -7,7 +7,6 @@ set -eu
 set -o pipefail
 
 # sanity checks
-source $_LIB/die
 [ -n "$IMAGE_BLOCK_DEVICE" ] || die "Image block device not set"
 
 # execute sfdisk with the given partitioning schema

elements/vm/block-device.d/10-partition

@@ -6,7 +6,6 @@ fi
 set -eu
 set -o pipefail
 
-source $_LIB/die
 [ -n "$IMAGE_BLOCK_DEVICE" ] || die "Image block device not set"
 
 # Create 2 partitions for PPC, one for PReP boot and other for root

lib/die

@@ -1,13 +1,13 @@
 #!/bin/bash
 # Copyright 2012 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
@@ -16,10 +16,11 @@
 
 # Prints "message" and exits
 # Usage: die "message"
-function die() {
+function die {
     local exitcode=$?
     set +o xtrace
     echo $@
     exit $exitcode
 }
 
+export -f die