Merge branch 'sparc' into 'master'

build-image: Exit in case of an unknown dist

See merge request Librem5/image-builder!155

build-image

@@ -132,6 +132,7 @@ setup_laniakea_spark_build() {
         distro=amber-phone
       ;;
       *) echo "Unknown dist"
+        exit 1
       ;;
   esac
   apt-get update