core: get rid of more references to scope, old terminology

lib/vagrant/ui.rb

@@ -76,7 +76,7 @@ module Vagrant
         opts = {}
         opts = data.pop if data.last.kind_of?(Hash)
 
-        target = opts[:scope] || ""
+        target = opts[:target] || ""
 
         # Prepare the data by replacing characters that aren't outputted
         data.each_index do |i|
@@ -225,7 +225,7 @@ module Vagrant
       def machine(type, *data)
         opts = {}
         opts = data.pop if data.last.is_a?(Hash)
-        opts[:scope] = @prefix
+        opts[:target] = @prefix
         data << opts
         @ui.machine(type, *data)
       end

test/unit/vagrant/ui_test.rb

@@ -166,13 +166,13 @@ describe Vagrant::UI::Prefixed do
   end
 
   describe "#machine" do
-    it "sets the scope option" do
-      ui.should_receive(:machine).with(:foo, scope: prefix)
+    it "sets the target option" do
+      ui.should_receive(:machine).with(:foo, target: prefix)
       subject.machine(:foo)
     end
 
     it "preserves existing options" do
-      ui.should_receive(:machine).with(:foo, :bar, foo: :bar, scope: prefix)
+      ui.should_receive(:machine).with(:foo, :bar, foo: :bar, target: prefix)
       subject.machine(:foo, :bar, foo: :bar)
     end
   end