Resolve Vagrant etcd unhealthy cluster error (#6630)

Vagrantfile

@@ -43,7 +43,7 @@ $num_instances ||= 3
 $instance_name_prefix ||= "k8s"
 $vm_gui ||= false
 $vm_memory ||= 2048
-$vm_cpus ||= 1
+$vm_cpus ||= 2
 $shared_folders ||= {}
 $forwarded_ports ||= {}
 $subnet ||= "172.18.8"