fix potential bug when running with thread, webui starter will overwrite ctx.obj
fix potential bug when running with thread, webui starter will overwrite ctx.obj

binux/pyspider,wangjun/pyspider,qiulimao/weblocust,qiulimao/weblocust,wangjun/pyspider,eromoe/pyspider,luoq/pyspider,nicozhang/pyspider,lashwang/pyspider,wonderay/pyspider,snakeliwei/pyspider,wangjun/pyspider,snakeliwei/pyspider,lashwang/pyspider,wonderay/pyspider,luoq/pyspider,binux/pyspider,luoq/pyspider,eromoe/pyspider,eromoe/pyspider,wonderay/pyspider,nicozhang/pyspider,snakeliwei/pyspider,binux/pyspider,nicozhang/pyspider,qiulimao/weblocust,lashwang/pyspider