* lib/cgi/util.rb: reverted r65505.  require_relative does not
  work for cgi/escape.so, as extension libraries are placed in
  other directories than ruby libraries.  [Bug #15206]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65511 b2dd03c8-39d4-4d8f-98ff-823fe69b080e