refixed the previous fix in IO#block_scanf

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@5903 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/scanf.rb

@@ -659,7 +659,8 @@ class IO
     last_spec = fstr.last_spec
     begin
       current = scanf(str)
-      final.push(yield(current)) unless current.empty?
+      break if current.empty?
+      final.push(yield(current))
     end until eof || fstr.last_spec_tried == last_spec
     return final
   end