Ensure that values passed to config.filter_run are respected when

running over DRb (using spork).

- Fixes rspec#554.

lib/rspec/core/configuration_options.rb

@@ -33,7 +33,7 @@ def drb_argv
       end
 
       def filter_manager
-        @filter_manager ||= FilterManager.new
+        @filter_manager ||= RSpec::configuration.filter_manager
       end
 
     private

spec/rspec/core/configuration_options_spec.rb

@@ -301,6 +301,13 @@
     end
   end
 
+  describe "#filter_manager" do
+    it "returns the same object as RSpec::configuration.filter_manager" do
+      config_options_object.filter_manager.
+        should be(RSpec::configuration.filter_manager)
+    end
+  end
+
   describe "sources: ~/.rspec, ./.rspec, custom, CLI, and SPEC_OPTS" do
     before(:each) do
       FileUtils.mkpath(File.expand_path("~"))