include OpenStack provider into the list of working providers

...as it works perfectly, thanks. :)
no need to do sudo in sudo
Fix the curl line to install the requested Chef version
Merge pull request #32 from tmatilai/fix-curl

Fix the curl line to install the requested Chef version
Merge pull request #28 from srenatus/patch-1

include OpenStack provider into the list of working providers
Document that newer than v1.1.x Vagrant is fine, too

The plugin works fine with at least Vagrant 1.2.x.

Also fix the RubyGems badge link.
Merge pull request #37 from tmatilai/readme

Document that newer than v1.1.x Vagrant is fine, too
fix CHANGELOG issue linking. fixes #29
Drop unneeded ConfigValidate action call

The built-in ConfigValidate action exits already earlier in the
middleware stack.
Merge branch 'pr/38'
update development/test dependancies
Ensure version is properly shell escaped. Fixes #27
update AWS acceptance test for latest `vagrant-aws`

The `ssh_username` has been removed and replaced by
`override.ssh.username`.
v1.1.1
Add vagrant-digitalocean to the list of supported providers

We even have acceptance tests for it.
Lock vagrant-rackspace down to v0.1.2

Version 0.1.3 has a conflicting fog dependency with vagrant-aws v0.3.0.
Don't install provider plugins in Travis

They are only needed on acceptance tests.
Compatibility with vagrant-aws v0.4.0

Next vagrant-aws release will remove its custom TimedProvision class and
use only the standard Builtin::Provision instead.

To support both old and new versions of the plugin, check if the
TimedProvision class is defined before using it.
Merge pull request #43 from tmatilai/travis

Fix development dependencies and Travis tests
Merge pull request #41 from tmatilai/readme-do

Add vagrant-digitalocean to the list of supported providers