SizeLimit violates k8s API convention

[kyessenov]

Is this a BUG REPORT or FEATURE REQUEST?:

Uncomment only one, leave it on its own line:

/kind bug

/kind feature

What happened:
kubernetes/community#306 added field SizeLimit in PR 85f030c. The field is marked as optional yet has the non-pointer type resource.Quantity. This is against the API convention that requires optional fields to be pointers.

As a consequence, k8s client-go library does not omit this field in serialization, breaking k8s 1.6 compatibility for this API.

What you expected to happen:
client-go 1.7 works with k8s 1.6 in pass-through object processing pipeline.

How to reproduce it (as minimally and precisely as possible):
See https://github.com/kubernetes/client-go/issues/257#issuecomment-319552550

Anything else we need to know?:

Environment:

• Kubernetes version (use kubectl version): 1.7
• Cloud provider or hardware configuration**: GKE
• OS (e.g. from /etc/os-release):
• Kernel (e.g. uname -a):
• Install tools:
• Others:

cc @caesarxuchao

[k8s-github-robot]

@kyessenov
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[kyessenov]

/assign @jingxu97

[kyessenov]

cc @andraxylia @ayj

[kyessenov]

Please cherry-pick this into 1.7 since this might affect everyone who uses client-go 1.7 for this API.