CleanMachineFolder action works with VBoxManage

lib/vagrant/action/vm/clean_machine_folder.rb

@@ -13,12 +13,12 @@ module Vagrant
         end
 
         def call(env)
-          clean_machine_folder
+          clean_machine_folder(env[:vm].driver.read_machine_folder)
           @app.call(env)
         end
 
-        def clean_machine_folder
-          folder = File.join(VirtualBox::Global.global.system_properties.default_machine_folder, "*")
+        def clean_machine_folder(machine_folder)
+          folder = File.join(machine_folder, "*")
 
           # Small safeguard against potentially unwanted rm-rf, since the default
           # machine folder will typically always be greater than 10 characters long.

lib/vagrant/driver/virtualbox.rb

@@ -146,6 +146,17 @@ module Vagrant
         return nil
       end
 
+      # This reads the folder where VirtualBox places it's VMs.
+      def read_machine_folder
+        execute("list", "systemproperties").split("\n").each do |line|
+          if line =~ /^Default machine folder:\s+(.+?)$/
+            return $1.to_s
+          end
+        end
+
+        nil
+      end
+
       # This reads the state for the given UUID. The state of the VM
       # will be returned as a symbol.
       def read_state