Ruby

transcode.c: empty encoding name

• transcode.c (rb_econv_set_replacement): target encoding name can
  be empty now. [ruby-core:69841] [Bug #11324]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51116 b2dd03c8-39d4-4d8f-98ff-823fe69b080e