AlmaLinux VM: report failures through the engine's error handler

The script replaced the engine's error_handler with one that sent the
failed command as the exit code, so every failure reached telemetry as
exit 199 "exit code not reported", without the failed command or
category. Its signal traps sent words instead of codes the same way.

It also ran its own unguarded apt-get update for libguestfs-tools, so a
host with the enterprise repository and no subscription (401) stopped
there. vm_prepare_cloud_image installs the tools itself, tolerating a
repository that fails to update.

vm/almalinux-vm.sh

@@ -24,18 +24,9 @@ THIN="discard=on,ssd=1,"
 set -e
 trap 'error_handler $LINENO "$BASH_COMMAND"' ERR
 trap cleanup EXIT
-trap 'post_update_to_api "failed" "INTERRUPTED"' SIGINT
-trap 'post_update_to_api "failed" "TERMINATED"' SIGTERM
-
-function error_handler() {
-  local exit_code="$?"
-  local line_number="$1"
-  local command="$2"
-  local error_message="${RD}[ERROR]${CL} in line ${RD}$line_number${CL}: exit code ${RD}$exit_code${CL}: while executing command ${YW}$command${CL}"
-  post_update_to_api "failed" "${command}"
-  echo -e "\n$error_message\n"
-  cleanup_vmid
-}
+trap 'post_update_to_api "failed" "130"' SIGINT
+trap 'post_update_to_api "failed" "143"' SIGTERM
+trap 'post_update_to_api "failed" "129"; exit 129' SIGHUP
 
 TEMP_DIR=$(mktemp -d)
 pushd "$TEMP_DIR" >/dev/null
@@ -126,16 +117,6 @@ post_to_api_vm
 
 vm_select_storage "$HN"
 
-# ==============================================================================
-# PREREQUISITES
-# ==============================================================================
-if ! command -v virt-customize &>/dev/null; then
-  msg_info "Installing libguestfs-tools"
-  $STD apt-get update
-  $STD apt-get install -y libguestfs-tools
-  msg_ok "Installed libguestfs-tools"
-fi
-
 msg_info "Retrieving the URL for the ${APP} Qcow2 Disk Image"
 ALMA_ARCH="$(vm_arch_resolve x86_64 aarch64)"
 URL="https://repo.almalinux.org/almalinux/${var_version}/cloud/${ALMA_ARCH}/images/AlmaLinux-${var_version}-GenericCloud-latest.${ALMA_ARCH}.qcow2"