don't announce 'Running filtered' when there are no filters

lib/rspec/core/world.rb

@@ -112,7 +112,7 @@ def announce_filters
             reporter.message(
               "No examples were matched. Perhaps #{exclusion_filter.description} is excluding everything?")
           end
-        else
+        elsif !filter_announcements.empty?
           reporter.message("Run filtered #{filter_announcements.join(', ')}")
         end
       end

spec/rspec/core/world_spec.rb

@@ -236,6 +236,17 @@ module RSpec::Core
           end
         end
       end
+
+      context "with examples" do
+        before { world.stub(:example_count) { 1 } }
+
+        context "with no filters" do
+          it "does not announce" do
+            reporter.should_not_receive(:message)
+            world.announce_filters
+          end
+        end
+      end
     end
 
     describe "#inclusion_filter" do