Added the Ubuntu image project for GCE.

The documentation:
https://cloud.google.com/compute/docs/operating-systems#ubuntu
shows that `ubuntu-os-cloud` is the proper project name.

builder/digitalocean: fix v2 api size

Signed-off-by: Vasiliy Tolstov <v.tolstov@selfip.ru>

Fix checksums link

Fix make updatedeps

Since the fork mitchellh/gophercloud-fork-40444fb is used for
gophercloud the folder rackspace/gophercloud does not exist and the
version fix does not have to happen.
Signed-off-by: BlackEagle <ike.devolder@gmail.com>

Extract Vagrant provider processing logic to a method

Qemu vagrant

Add support for building QEMU images from pre-existing image files

Fixes #1334, Add power on retry to ESXi Driver.

Salt masterless tidy up

add digitalocean v2 api support

buidler/vmware-esxi: Add configuration options for the remote location to cache ISO and floppy files

#1191 - Add VMWare virtualhw.version configuration option under 'version'

builder/vmware: accept SATA drives on root VMX

builder/amazon: Extend timeout and allow user override [GH-1533]