Fixed the interactive install issues with the vagrant provison step

Author: kristenjacobs

4-overlay-network/Vagrantfile

@@ -3,6 +3,7 @@
 
 $script = <<SCRIPT
 echo "cd /vagrant" >> /home/vagrant/.bashrc
+export DEBIAN_FRONTEND=noninteractive
 dpkg -i --force-all /vagrant/pkg/socat_1.7.3.1-1_amd64.deb
 dpkg -i --force-all /vagrant/pkg/geoip-database-extra_20160408-1_all.deb
 dpkg -i --force-all /vagrant/pkg/javascript-common_11_all.deb
@@ -22,8 +23,6 @@ dpkg -i --force-all /vagrant/pkg/libwireshark-data_2.2.6+g32dac6a-2ubuntu0.16.04
 dpkg -i --force-all /vagrant/pkg/libwireshark8_2.2.6+g32dac6a-2ubuntu0.16.04_amd64.deb
 dpkg -i --force-all /vagrant/pkg/wireshark-common_2.2.6+g32dac6a-2ubuntu0.16.04_amd64.deb
 dpkg -i --force-all /vagrant/pkg/tshark_2.2.6+g32dac6a-2ubuntu0.16.04_amd64.deb
-# To work around a VirtualBox bug causing the networking to be broken when the VM starts.
-systemctl restart networking
 SCRIPT
 
 Vagrant.configure(2) do |config|