fix executable modes on .sh`s; add pre-system-test.sh hook (googleapis#356)

Author: jkwlui

handwritten/storage/.kokoro/docs.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+
+# Copyright 2018 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# nodejs-storage's system tests require additional project and
+# system test key
+export GCN_STORAGE_2ND_PROJECT_ID=gcloud-node-whitelist-ci-tests
+export GCN_STORAGE_2ND_PROJECT_KEY=${KOKORO_GFILE_DIR}/no-whitelist-key.json

handwritten/storage/.kokoro/lint.sh

@@ -21,6 +21,11 @@ export GOOGLE_APPLICATION_CREDENTIALS=${KOKORO_GFILE_DIR}/service-account.json
 
 cd $(dirname $0)/..
 
+# Run a pre-test hook, if a pre-system-test.sh is in the project
+if [ -f .kokoro/pre-system-test.sh ]; then
+    . .kokoro/pre-system-test.sh
+fi
+
 npm install
 
 npm run system-test