Fixed Kernel#scanf to propagate code block

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@5864 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/scanf.rb

@@ -691,7 +691,7 @@ end
 
 module Kernel
   private
-  def scanf(fs)
-    STDIN.scanf(fs)
+  def scanf(fs,&b)
+    STDIN.scanf(fs,&b)
   end
 end