Update/remove reference to `.ruby-version`

[mcwumbly]

In the Create a Manifest doc it says:

Install the Ruby version listed in the .ruby-version file of the cf-release repository. You can manage your Ruby versions using rvm, rbenv, or chruby

https://github.com/cloudfoundry/docs-deploying-cf/blob/master/boshlite/create_a_manifest.html.md.erb#L64

But the .ruby-version file was recently removed:

https://github.com/cloudfoundry/cf-release/issues/1025

Should this line just be delete from the docs or changed to say something about the last known working ruby version? /cc @Amit-PivotalLabs

[cf-gitbot]

We have created an issue in Pivotal Tracker to manage this:

https://www.pivotaltracker.com/story/show/131048969

The labels on this github issue will be updated when the story is started.

[Amit-PivotalLabs]

Thanks for the catch @mcwumbly, we should remove that line. Gonna move the tracker story to a different icebox /cc @animatedmax @dsabeti

[jaresty]

Created pull request

[animatedmax]

Thanks!