fix(controller): check image for hostname

Older images may still have a hostname in the database. Checking if
it has a hostname in the image name ensures backwards compatibility.
docs(gce): instructions for running Deis in Google Compute Engine

Adding instructions and script for running on Google Compute Engine. This changes existing CoreOS user-data to set permissions as strings instead of integers. PyYAML interperets integers preceded by 0 to be octal. 0755 would become 493 when converted.

closes #1036
chore(client): update requests to 2.3.0

https://github.com/kennethreitz/requests/releases/tag/v2.3.0
Merge pull request #1495 from andyshinn/google_compute_engine_tutorial

docs(gce): Instructions for running Deis in Google Compute Engine
Merge pull request #1589 from mboersma/update-requests

chore(client): update requests to 2.3.0
Merge pull request #1538 from deis/check-hostname

fix(controller): check image for hostname