When syncNetworkConfig we should update defaultNetName to avoid getDefaultNetwork error

[changyaowei]

When conf file change, especially confList.Name changed, by loadNetworks func, we can get a new networks and defaultNetname. In now, if defaultNetname not empty, we will not update it , if like so, we will get nil when we call getDefaultNetwork func, because of the network which name is defaultNetname not exist. and if we call status func ,we will get 'Missing CNI default network'

[openshift-ci-robot]

Thanks for your pull request. Before we can look at it, you'll need to add a 'DCO signoff' to your commits.

📝 Please follow instructions in the contributing guide to update your commits with the DCO

Full details of the Developer Certificate of Origin can be found at developercertificate.org.

The list of commits missing DCO signoff:

• 3d4adbb when syncNetworkConfig we should update defaultNetName to avoid get getDefaultNetwork error

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository. I understand the commands that are listed here.

[openshift-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: changyaowei
To complete the pull request process, please assign rajatchopra
You can assign the PR to them by writing /assign @rajatchopra in a comment when ready.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[dcbw]

This is effectively a dupe of #38 and #31 and is being fixed in a somewhat different way.

[dcbw]

See #38 (comment) for more details.

[dcbw]

Done slightly differently in #58