fix(app-emulation/google-startup-scripts): don't install boto

skip installing the boto scripts since we don't ship python or gsutil.
fix(coreos-base/oem-gce): call run-startup-scripts

I didn't realize that google-startup-scripts has two services it needs.
First it calls onboot which essentially just downloads the
startup-script. Then there is a second service that actually calls the
script.
Merge pull request #520 from philips/no-boto-tools-on-gce

fix(app-emulation/google-startup-scripts): don't install boto