ci: Remove /ro_base bind mount

Just set the bind mount to BASE_READ_ONLY_DIR, which allows to drop one
line of code and makes the code easier to understand.

ci/test/04_install.sh

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 #
-# Copyright (c) 2018-2022 The Bitcoin Core developers
+# Copyright (c) 2018-present The Bitcoin Core developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
@@ -32,13 +32,13 @@ if [ -z "$DANGER_RUN_CI_ON_HOST" ]; then
 
   # shellcheck disable=SC2086
   CI_CONTAINER_ID=$(docker run $CI_CONTAINER_CAP --rm --interactive --detach --tty \
-                  --mount type=bind,src=$BASE_READ_ONLY_DIR,dst=/ro_base,readonly \
+                  --mount "type=bind,src=$BASE_READ_ONLY_DIR,dst=$BASE_READ_ONLY_DIR,readonly" \
                   --mount "type=volume,src=${CONTAINER_NAME}_ccache,dst=$CCACHE_DIR" \
                   --mount "type=volume,src=${CONTAINER_NAME}_depends,dst=$DEPENDS_DIR" \
                   --mount "type=volume,src=${CONTAINER_NAME}_previous_releases,dst=$PREVIOUS_RELEASES_DIR" \
                   --env-file /tmp/env \
-                  --name $CONTAINER_NAME \
-                  $CONTAINER_NAME)
+                  --name "$CONTAINER_NAME" \
+                  "$CONTAINER_NAME")
   export CI_CONTAINER_ID
   export CI_EXEC_CMD_PREFIX="docker exec ${CI_CONTAINER_ID}"
 else
@@ -56,7 +56,7 @@ export -f CI_EXEC
 # Normalize all folders to BASE_ROOT_DIR
 CI_EXEC rsync --archive --stats --human-readable "${BASE_READ_ONLY_DIR}/" "${BASE_ROOT_DIR}" || echo "Nothing to copy from ${BASE_READ_ONLY_DIR}/"
 CI_EXEC "${BASE_ROOT_DIR}/ci/test/01_base_install.sh"
-CI_EXEC rsync --archive --stats --human-readable /ro_base/ "${BASE_ROOT_DIR}" || echo "Nothing to copy from ro_base"
+
 # Fixes permission issues when there is a container UID/GID mismatch with the owner
 # of the git source code directory.
 CI_EXEC git config --global --add safe.directory \"*\"