drb.rb: do not wait handler threads

* lib/drb/drb.rb (stop_service): just stop but do not wait handler
  threads.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49312 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/drb/drb.rb

@@ -1467,13 +1467,12 @@ module DRb
       if  Thread.current['DRb'] && Thread.current['DRb']['server'] == self
         Thread.current['DRb']['stop_service'] = true
       else
-        threads = [@thread, *@grp.list]
         if @protocol.respond_to? :shutdown
           @protocol.shutdown
         else
-          threads.each {|thread| thread.kill} # xxx: Thread#kill
+          [@thread, *@grp.list].each {|thread| thread.kill} # xxx: Thread#kill
         end
-        threads.each {|thread| thread.join}
+        @thread.join
       end
     end