update travis.yml with build variable and remove node stable build
update travis.yml with build variable and remove node stable build

ciena-frost/ember-frost-core,EWhite613/ember-frost-core,EWhite613/ember-frost-core,ciena-frost/ember-frost-core,dafortin/ember-frost-core,EWhite613/ember-frost-core,ciena-frost/ember-frost-core,dafortin/ember-frost-core,dafortin/ember-frost-core