website/www: blog post on vagrant 1.5 plugin improvements
website/docs: don't capitalize commands docs
website/docs: document vagrant share functionality
website/docs: document vagrant login
website/www: move plugin blog to 02-27
provisioners/ansible: remove an unused variable

Sorry, I missed that point in GH-2991 review.

[ci skip]
website/www: fix title
website/www: fix share URL