chore: one more workaround for repo-tools EPERM (#26)

Author: alexander-fenster

packages/google-cloud-bigquery-datatransfer/.circleci/config.yml

@@ -176,7 +176,12 @@ jobs:
                 -k "${SYSTEM_TESTS_ENCRYPTION_KEY}"
       - run:
           name: Install modules and dependencies.
-          command: npm install
+          command: |-
+            npm install
+            repo_tools="node_modules/@google-cloud/nodejs-repo-tools/bin/tools"
+            if ! test -x "$repo_tools"; then
+              chmod +x "$repo_tools"
+            fi
       - run:
           name: Run system tests.
           command: npm run system-test