Revert "Prefer double-quoted strings in Ruby code"

This reverts commit ded21f2a76fe53211699ecc3c896b87f56f1abfe.

This changes seems to have broken all the Jenkins builds, Sauce reports "Unable to pick a platform" for every build in every repo.

Change-Id: Ie321d961687423379e237c0cf35da29965f2dc71