Revert "Allow backup to be run as non-root user (#366)" (#370)

This reverts commit f64aaa6e24.

test/nonroot/run.sh

@@ -1,27 +0,0 @@
-#!/bin/sh
-
-set -e
-
-cd "$(dirname "$0")"
-. ../util.sh
-current_test=$(basename $(pwd))
-
-export LOCAL_DIR=$(mktemp -d)
-
-docker compose up -d --quiet-pull
-sleep 5
-
-docker compose logs backup
-
-# conf.d is used to confirm /etc files are also accessible for non-root users
-docker compose exec backup /bin/sh -c 'set -a; source /etc/dockervolumebackup/conf.d/01conf.env; set +a && backup'
-
-sleep 5
-
-expect_running_containers "3"
-
-if [ ! -f "$LOCAL_DIR/backup/test.tar.gz" ]; then
-  fail "Could not find archive."
-fi
-pass "Archive was created."
-