misc/upgrades-installed-check: handle apt-get errors

misc/upgrades-installed-check

@@ -15,6 +15,8 @@ if [ -e /etc/system-release ]; then
    [ "$exit_code" -eq 0 ] && echo "true"
 else
    ## Debian
+   set -e
+   set -o pipefail
    apt_get_output="$(LANG="C" apt-get -s upgrade 2>&1)"
    exit_code="$?"
    echo "$apt_get_output" | awk "/^Inst/{ print $2 }" | [ "$(wc -L)" -eq 0 ] && echo "true" || echo "false"