kernel/v2: box is optional if clone is set

plugins/kernel_v2/config/vm.rb

@@ -559,7 +559,7 @@ module VagrantPlugins
       def validate(machine)
         errors = _detected_errors
 
-        if !box && !machine.provider_options[:box_optional]
+        if !box && !clone && !machine.provider_options[:box_optional]
           errors << I18n.t("vagrant.config.vm.box_missing")
         end
 

plugins/providers/virtualbox/action/match_mac_address.rb

@@ -7,6 +7,9 @@ module VagrantPlugins
         end
 
         def call(env)
+          # If we cloned, we don't need a base mac, it is already set!
+          return @app.call(env) if env[:machine].config.vm.clone
+
           raise Vagrant::Errors::VMBaseMacNotSpecified if !env[:machine].config.vm.base_mac
 
           # Create the proc which we want to use to modify the virtual machine