Revert "use pull request to test travis, don't merge it!"

This reverts commit 58480d9d65f0cb6c31dff7f8f3b022754203c2ad.
Revert "update travics.yaml"

This reverts commit fcd7a66775f4d3539ef6f923e043b7e3aff778bd.
don't merge it, again. just use pull request to force build