vendor: Use dep instead of glide and prune it

[gaocegege]

• Use dep instead of glide
• Remove unused packages from vendor tree via dep prune -v +27,065 −1,698,564
• Add code-generator in vendor and regenerate

/assign @zjj2wry @jlewi

Close #556

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This change is 

[gaocegege]

The first two commits are auto generated. 27d46f1 and 1bc19e5 are manually changed by me. PTAL

[coveralls]

Coverage decreased (-11.4%) to 38.951% when pulling 1bc19e5 on gaocegege:dep into 60d25c4 on kubeflow:master.

[coveralls]

Coverage decreased (-11.4%) to 38.951% when pulling 1bc19e5 on gaocegege:dep into 60d25c4 on kubeflow:master.

[coveralls]

Coverage decreased (-0.08%) to 49.4% when pulling 0a752d3 on gaocegege:dep into 07fd2d6 on kubeflow:master.

[gaocegege]

The error in Travis CI is fixed in #548

[jlewi]

Why switch to dep instead of glide? We've been using glide in most places I think.

/cc @wbuchwalter

[gaocegege]

Because of #541

As you see, we reduced the code base significantly.

+ 27,065
- 1,698,564

Besides this, dep is more popular and avtive than glide: https://go.libhunt.com/compare-dep-vs-glide

[jlewi]

I don't have a strong oppinion but as I commented on the issue lets try to get consensus and adopt a single tool for all of Kubeflow.

[gaocegege]

Per the discussion #556 , we come to an agreement. And I solved the problem in Travis, PTAL @jlewi @ScorpioCPH @zjj2wry

[zjj2wry]

/lgtm thank you do this ~

[gaocegege]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: gaocegege, zjj2wry

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[gaocegege]

It seems that my approve does not work

/assign @jlewi @ScorpioCPH