Method::Patcher should preserve method visibility

(Works around https://github.com/rubinius/rubinius/issues/2248)

lib/pry/method/patcher.rb

@@ -97,7 +97,8 @@ class Pry
       def wrap_for_owner(source)
         Pry.current[:pry_owner] = method.owner
         owner_source = definition_for_owner(source)
-        "Pry.current[:pry_owner].class_eval do; #{owner_source}\nend"
+        visibility_fix = "#{method.visibility.to_s} #{method.name.to_sym.inspect}"
+        "Pry.current[:pry_owner].class_eval do; #{owner_source}\n#{visibility_fix}\nend"
       end
 
       # Update the new source code to have the correct Module.nesting.

spec/method/patcher_spec.rb

@@ -24,4 +24,11 @@ describe Pry::Method::Patcher do
     @method.redefine "def @x.test; :after; end\n"
     Pry::Method(@x.method(:test)).source.strip.should == "def @x.test; :after; end"
   end
+
+  it "should preserve visibility" do
+    class << @x; private :test; end
+    @method.visibility.should == :private
+    @method.redefine "def @x.test; :after; end\n"
+    Pry::Method(@x.method(:test)).visibility.should == :private
+  end
 end