google.golang.org/api/compute/v0.beta again changed public interfaces which causes breakages in other build environments. Update everything to HEAD.
For sending emails from appengine apps.
dep tool vendored too much code (100MB) including tests and unused packages. godep vendored significantly less (12MB) without tests and unused packages. The main advantage is that pre-Go1.9 toolchain does not run tests of all vendor packages now.