Drop Node versions that don't run current Rollup from travis.yml
Drop Node versions that don't run current Rollup from travis.yml

mysticatea/acorn,marijnh/acorn,mysticatea/acorn,TimothyGu/acorn,ternjs/acorn,TimothyGu/acorn,mysticatea/acorn,ternjs/acorn,ternjs/acorn,marijnh/acorn,TimothyGu/acorn,marijnh/acorn