Make spec work for ruby 1.9.3 and possibly other versions.

spec/pryrc_spec.rb

@@ -39,11 +39,11 @@ describe Pry do
 
     it "should not load the pryrc if pryrc's directory permissions do not allow this" do
       Dir.mktmpdir do |dir|
-        FileUtils.chmod 0, dir
+        File.chmod 0000, dir
         Pry::LOCAL_RC_FILE.replace File.join(dir, '.pryrc')
         Pry.config.should_load_rc = true
         expect { Pry.start(self, :input => StringIO.new("exit-all\n"), :output => StringIO.new) }.to_not raise_error
-        FileUtils.chmod 777, dir
+        File.chmod 0777, dir
       end
     end