Don't run setup addons twice
Don't run setup addons twice

The setup stage will be run just like any other stage through the Stages
module, which will in turn call this method, causing any addons using
the setup stage to run twice.

kidaa/travis-build,aceofspades/travis-build,aceofspades/travis-build,akoeplinger/travis-build,vinaykaradia/travisBuild-clone,luoqii/travis-build,whip112/travis-build,Distelli/travis-build,Acidburn0zzz/travis-build,tmccombs/travis-build,Tiger66639/travis-build,final-ci/travis-build,paultcochrane/travis-build,JuliaCI/travis-build,paultcochrane/travis-build,Acidburn0zzz/travis-build,kidaa/travis-build,vinaykaradia/travisBuild-clone,andyli/travis-build,andyli/travis-build,will/travis-build,tmccombs/travis-build,gavioto/travis-build,will/travis-build,final-ci/travis-build,jhass/travis-build,Joshua-Anderson/travis-build,aceofspades/travis-build,craigcitro/travis-build,saucelabs/travis-build,whip112/travis-build,dirk/travis-build,kevmoo/travis-build,dirk/travis-build,vinaykaradia/travisBuild-clone,wereHamster/travis-build,a14n/travis-build,wereHamster/travis-build,Distelli/travis-build,luoqii/travis-build,vlamanna/travis-build,tianon/travis-build,Joshua-Anderson/travis-build,will/travis-build,vlamanna/travis-build,gavioto/travis-build,craigcitro/travis-build,tianon/travis-build,jhass/travis-build,Tiger66639/travis-build,kevmoo/travis-build,vlamanna/travis-build,Joshua-Anderson/travis-build,saucelabs/travis-build,lrowe/travis-build,a14n/travis-build,final-ci/travis-build,JuliaCI/travis-build,paultcochrane/travis-build,lrowe/travis-build,wereHamster/travis-build,akoeplinger/travis-build