Update FreeBSD configure_networks with less shell specifics
website/docs: Links to new downloads page

Fixes #2623 and hashicorp/docs.vagrantup.com#45

[ci skip]
website/docs: Fix example of v1 config option invalid in v2

Fix the name of the old v1 option, `config.vm.forward_port`, used as an example of an invalid option in v2.
Update CHANGELOG

/cc @phinze style :)
Merge pull request #2620 from ShonM/master

guests/freebsd: Update FreeBSD configure_networks with less shell specifics
Update CHANGELOG
guests/redhat: don't ifdown non-existent interfaces [GH-2614]
mention chef.delete_node and chef.delete_client methods in the DOCS
guests/redhat: Don't error if ifdown fails [GH-2614]
Update is_port_open.rb
Merge pull request #2629 from lndbrg/patch-1

core: update is_port_open.rb comment
Merge pull request #2628 from makern/ifdown-fix

guests/redhat: Don't error if ifdown fails [GH-2614]
Merge pull request #2627 from scalp42/chef_delete

website/docs: mention chef.delete_node and chef.delete_client methods
fix path to acceptance test contexts in example
Merge pull request #2631 from miketheman/fix_acceptance_path

fix path to acceptance test contexts in example
Fixes networking private network URL
Merge pull request #2635 from bbonamin/master

Fixes networking private network URL