build: remove opensuse build infra

- VPP on opensuse has not been supported
  for several releases.

Type: fix

Signed-off-by: Dave Wallace <dwallacelf@gmail.com>
Change-Id: I2b5316ad5c20a843b8936f4ceb473f932a5338d9

extras/vagrant/Vagrantfile

@@ -9,9 +9,6 @@ Vagrant.configure(2) do |config|
     config.vm.box = "centos/7"
     config.vm.box_version = "1708.01"
     config.ssh.insert_key = false
-  elsif distro == 'opensuse'
-    config.vm.box = "opensuse/openSUSE-42.3-x86_64"
-    config.vm.box_version = "1.0.4.20170726"
   elsif distro == 'ubuntu1804'
     config.vm.box = "bento/ubuntu-18.04"
   else