Vagrant was not behaving correctly in configurations where there was a static IP on a VirtualBox `intnet` interface and a DHCP `:hostonly` interface configured. Since `machine_ip` attempted to get static addresses `||` dynamic addresses, it would simply use the static machine address and continue. This commit corrects this behaviour by collecting all static and dynamic addresses into the `machine_ip` array instead of just one or the other. The result of this is a correctly generated `/etc/exports` on the host machine, allowing NFS mounts to work correctly in this type of environment.
Vagrant Core Plugins
These are plugins that ship with Vagrant. Vagrant core uses its own plugin system to power a lot of the core pieces that ship with Vagrant. Each plugin will have its own README which explains its specific role.