CI: Vagrant don't download_force_cache

Vagrantfile

@@ -55,7 +55,7 @@ $network_plugin ||= "flannel"
 # Setting multi_networking to true will install Multus: https://github.com/intel/multus-cni
 $multi_networking ||= false
 $download_run_once ||= "True"
-$download_force_cache ||= "True"
+$download_force_cache ||= "False"
 # The first three nodes are etcd servers
 $etcd_instances ||= $num_instances
 # The first two nodes are kube masters