use clock_gettime to avoid object creation

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48582 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/net/http.rb

@@ -915,7 +915,7 @@ module Net   #:nodoc:
             HTTPResponse.read_new(@socket).value
           end
           if @ssl_session and
-             Time.now < @ssl_session.time + @ssl_session.timeout
+             Process.clock_gettime(Process::CLOCK_REALTIME) < @ssl_session.time.to_f + @ssl_session.timeout
             s.session = @ssl_session if @ssl_session
           end
           # Server Name Indication (SNI) RFC 3546