test_keyword.rb: suppress warning

* test/ruby/test_keyword.rb (TestKeywordArguments#m1): suppress
  argument prefix warning.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39505 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_keyword.rb

@@ -246,7 +246,7 @@ class TestKeywordArguments < Test::Unit::TestCase
   end
 
   def m1(*args)
-    yield *args
+    yield(*args)
   end
 
   def test_block