fog/fog — pull request #2064 by amoghe (2013-08-11 23:34:28+00:00)
Title: Accept/propagate the correct params when creating a new disk

This patch tries to match the [API](https://developers.google.com/compute/docs/reference/latest/disks/insert) w.r.t disk insert(create). The user is now expected to pass one of ```image_name``` or ```size``` and ```snapshot``` when creating a disk.