Setup travis as CI env

[k82cn]

For now, found the follow two issues here:

• no hack/verify-gofmt.sh for make verify
• both e2e-test and e2e-test-kind miss scripts

[TommyLike]

First issue is fixed by renaming the sh file, but still need more investigation on verify-golint subtask.

[k82cn]

Add related pkg to hack/.golint_failures is fine for now to fix verify-golint error.

[TommyLike]

@k82cn It's fixed in master branch now.

[k82cn]

CI is running now although some e2e tests are failed.