Allow dummy config to eval config blocks to set instance variables

lib/vagrant/config/v2/dummy_config.rb

@@ -5,8 +5,18 @@ module Vagrant
       # to it. Anything, and it just appears to keep working.
       class DummyConfig
         def method_missing(name, *args, &block)
+          # Trying to define a variable
+          if name.to_s.match(/[\w]*=/)
+            var_name = "@#{name.to_s.split("=")[0]}"
+            self.instance_variable_set(var_name, args[0])
+          else
             DummyConfig.new
           end
+        end
+
+        def merge(c)
+          c
+        end
 
         def set_options(options)
           options.each do |key, value|

parse_vagrantfile.rb

@@ -25,6 +25,7 @@ def stringify_symbols(m)
     end
     if v.is_a?(Array)
       v.map!{|sk| sk.is_a?(Symbol) ? sk.to_s : sk}
+      stringify_symbols(v)
       next
     end
     k = k.to_s if k.is_a?(Symbol)
@@ -172,8 +173,6 @@ def parse_vagrantfile(path)
     extract_synced_folders(config_vm_proto.synced_folders, vm_config.synced_folders)
     extract_provider(config_vm_proto.providers, vm_config)
 
-    # require "pry-byebug"; binding.pry
-
     machine_configs << Hashicorp::Vagrant::VagrantfileComponents::MachineConfig.new(
       name: mach.to_s,
       config_vm: config_vm_proto,