Fix Chrome version substitution
Fix Chrome version substitution

This may not be a _bug_, but looks like we're not subbing CHROME_VERSION
into our curl in the install-Chrome script. This fixes that, and also
retrieves it from the official Chrome mirror--not sure why we were
retrieving it from our own S3 bucket.

Also changed some quotes so we never run into word splitting issues,
blablabla probably never gonna happen but it makes shellcheck happy.

Pivotal Story: [#157209965](https://www.pivotaltracker.com/story/show/157209965)

goodeggs/travis-utils