Add final summary step to buildbot.
Add final summary step to buildbot.

This avoids the publish step being reported as a failure
when one or more builds fail.

Also, only perform publish step on linux bots.

R=binji@chromium.org

Review URL: https://codereview.chromium.org/195413003

git-svn-id: 84b3587ce119b778414dcb50e18b7479aacf4f1d@1157 7dad1e8b-422e-d2af-fbf5-8013b78bd812

yeyus/naclports,binji/naclports,Schibum/naclports,kosyak/naclports_samsung-smart-tv,clchiou/naclports,dtkav/naclports,kosyak/naclports_samsung-smart-tv,clchiou/naclports,yeyus/naclports,clchiou/naclports,Schibum/naclports,binji/naclports,binji/naclports,kosyak/naclports_samsung-smart-tv,dtkav/naclports,Schibum/naclports,yeyus/naclports,kuscsik/naclports,dtkav/naclports,clchiou/naclports,kuscsik/naclports,Schibum/naclports,dtkav/naclports,kosyak/naclports_samsung-smart-tv,Schibum/naclports,kuscsik/naclports,kuscsik/naclports,yeyus/naclports,kosyak/naclports_samsung-smart-tv,binji/naclports,yeyus/naclports,binji/naclports,kuscsik/naclports,clchiou/naclports,Schibum/naclports,dtkav/naclports,yeyus/naclports