vagrant: update image name of boxcutter debian7 boxes

debian711* is 404.

Vagrantfile

@@ -385,7 +385,7 @@ Vagrant.configure(2) do |config|
   end
 
   config.vm.define "wheezy32" do |b|
-    b.vm.box = "boxcutter/debian711-i386"
+    b.vm.box = "boxcutter/debian7-i386"
     b.vm.provision "packages prepare wheezy", :type => :shell, :inline => packages_prepare_wheezy
     b.vm.provision "packages debianoid", :type => :shell, :inline => packages_debianoid
     b.vm.provision "install pyenv", :type => :shell, :privileged => false, :inline => install_pyenv("wheezy32")
@@ -398,7 +398,7 @@ Vagrant.configure(2) do |config|
   end
 
   config.vm.define "wheezy64" do |b|
-    b.vm.box = "boxcutter/debian711"
+    b.vm.box = "boxcutter/debian7"
     b.vm.provision "packages prepare wheezy", :type => :shell, :inline => packages_prepare_wheezy
     b.vm.provision "packages debianoid", :type => :shell, :inline => packages_debianoid
     b.vm.provision "install pyenv", :type => :shell, :privileged => false, :inline => install_pyenv("wheezy64")