ensure static network changes don't update DNS

`PEERDNS=no` ensures the DNS settings (from /etc/resolv.conf) are not
overwritten when we do an ifdown/ifup cycle to apply Vagrant's
changes.
`static` is not a valid BOOTPROTO value

Valid BOOTPROTO choices include: `none`, `bootp` and `dhcp`. In the case
of static network addresses `none` should be used.
Merge pull request #1554 from schisamo/redhat-network-fixes

Red Hat / Fedora networking template fixes