reduce test vm memory

test/Vagrantfile

@@ -45,6 +45,7 @@ Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
   config.vm.provider :virtualbox do |vb|
     vb.customize ["modifyvm", :id, "--natdnshostresolver1", "off"]
     vb.customize ["modifyvm", :id, "--natdnsproxy1", "off"]
+    vb.memory = 384
   end
 
   # Disable Vagrant 1.7 per host insecure key replacement