CentOS 6.5 and Ubuntu 14.04 Vagrant VMs getting assigned domain name

I'm provisioning a CentOS 6.5 and Ubuntu 14.04.1 LTS VM with Vagrant running under VirtualBox. I'm using Vagrantfiles to set the hostnames and IPs, but when I boot them, for example, instead of server1 the FQDN becomes server1.domain.com. The host machine is a Windows Machine on an Active Directory domain (domain.com). I just want the FQDN to be server1 with no domain name. How can I achieve this, preferably using just the Vagrantfiles?

Here is one of the Vagrantfiles