Minor Travis fixes (#373)

* Add `set -e` to trigger script

This will cause the script to fail immediately if one of the commands
fails.

* Update Travis token environment variable

Having this in the Travis file is difficult to figure out, so it's
easier to put it in the Travis settings.

.travis.yml

@@ -2,9 +2,6 @@ sudo: false
 language: node_js
 node_js:
   - "0.10"
-env:
-  global:
-    secure: "15QWA6igmMx1I2YlDrdkxsOi2YJIWNrXmgEtfEoCWR7eJQW2bkUDdzTXYFzxaEPIVMEgO+0pxfGwMWn/9MBhnXCLu9x0f0KqJ/0YfCGXHW21g8J+31zypdiCiw/Ir/dxazP9wpvWFhuqjo9X35zP3Md7TC8u+20uW2Q5KUVyqZM="
 before_install:
   - openssl aes-256-cbc -K $encrypted_909ac1036a94_key -iv $encrypted_909ac1036a94_iv -in .travis/govuk_frontend_toolkit_push.enc -out ~/.ssh/id_rsa -d
   - chmod 600 ~/.ssh/id_rsa

.travis/README.md

@@ -16,8 +16,9 @@ is the only way we can find that Travis can trigger another job.
 In this case, the downstream jobs publish the frontend toolkit to npm
 and RubyGems.
 
-The `env.global.secure` in `/.travis.yml` contains a Travis token that
-belongs to [@alexmuller](https://github.com/alexmuller) - as far as we
+The [Travis settings](https://travis-ci.org/alphagov/govuk_frontend_toolkit/settings)
+contains a Travis token that belongs to
+[@alexmuller](https://github.com/alexmuller) - as far as we
 can tell there's no way to generate one of these that isn't related to
 a specific user. This token could be replaced with a generic bot account
 if we created one.

trigger.sh

@@ -1,5 +1,7 @@
 #!/bin/bash
 
+set -e
+
 PAYLOAD='{
 "request": {
   "branch": "master"